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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/ipc/sem.c
4 * Copyright (C) 1992 Krishna Balasubramanian
5 * Copyright (C) 1995 Eric Schenk, Bruno Haible
6 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * /proc/sysvipc/sem support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
8 *
9 * SMP-threaded, sysctl's added
Christian Kujau624dffc2006-01-15 02:43:54 +010010 * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Enforced range limit on SEM_UNDO
Alan Cox046c6882009-01-05 14:06:29 +000012 * (c) 2001 Red Hat Inc
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 * Lockless wakeup
14 * (c) 2003 Manfred Spraul <manfred@colorfullife.com>
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -080015 * (c) 2016 Davidlohr Bueso <dave@stgolabs.net>
Manfred Spraulc5cf6352010-05-26 14:43:43 -070016 * Further wakeup optimizations, documentation
17 * (c) 2010 Manfred Spraul <manfred@colorfullife.com>
Steve Grubb073115d2006-04-02 17:07:33 -040018 *
19 * support for audit of ipc object properties and permission changes
20 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaeve3893532006-10-02 02:18:22 -070021 *
22 * namespaces support
23 * OpenVZ, SWsoft Inc.
24 * Pavel Emelianov <xemul@openvz.org>
Manfred Spraulc5cf6352010-05-26 14:43:43 -070025 *
26 * Implementation notes: (May 2010)
27 * This file implements System V semaphores.
28 *
29 * User space visible behavior:
30 * - FIFO ordering for semop() operations (just FIFO, not starvation
31 * protection)
32 * - multiple semaphore operations that alter the same semaphore in
33 * one semop() are handled.
34 * - sem_ctime (time of last semctl()) is updated in the IPC_SET, SETVAL and
35 * SETALL calls.
36 * - two Linux specific semctl() commands: SEM_STAT, SEM_INFO.
37 * - undo adjustments at process exit are limited to 0..SEMVMX.
38 * - namespace are supported.
39 * - SEMMSL, SEMMNS, SEMOPM and SEMMNI can be configured at runtine by writing
40 * to /proc/sys/kernel/sem.
41 * - statistics about the usage are reported in /proc/sysvipc/sem.
42 *
43 * Internals:
44 * - scalability:
45 * - all global variables are read-mostly.
46 * - semop() calls and semctl(RMID) are synchronized by RCU.
47 * - most operations do write operations (actually: spin_lock calls) to
48 * the per-semaphore array structure.
49 * Thus: Perfect SMP scaling between independent semaphore arrays.
50 * If multiple semaphores in one array are used, then cache line
51 * trashing on the semaphore array spinlock will limit the scaling.
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -070052 * - semncnt and semzcnt are calculated on demand in count_semcnt()
Manfred Spraulc5cf6352010-05-26 14:43:43 -070053 * - the task that performs a successful semop() scans the list of all
54 * sleeping tasks and completes any pending operations that can be fulfilled.
55 * Semaphores are actively given to waiting tasks (necessary for FIFO).
56 * (see update_queue())
57 * - To improve the scalability, the actual wake-up calls are performed after
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -080058 * dropping all locks. (see wake_up_sem_queue_prepare())
Manfred Spraulc5cf6352010-05-26 14:43:43 -070059 * - All work is done by the waker, the woken up task does not have to do
60 * anything - not even acquiring a lock or dropping a refcount.
61 * - A woken up task may not even touch the semaphore array anymore, it may
62 * have been destroyed already by a semctl(RMID).
Manfred Spraulc5cf6352010-05-26 14:43:43 -070063 * - UNDO values are stored in an array (one per process and per
64 * semaphore array, lazily allocated). For backwards compatibility, multiple
65 * modes for the UNDO variables are supported (per process, per thread)
66 * (see copy_semundo, CLONE_SYSVSEM)
67 * - There are two lists of the pending operations: a per-array list
68 * and per-semaphore list (stored in the array). This allows to achieve FIFO
69 * ordering without always scanning all pending operations.
70 * The worst-case behavior is nevertheless O(N^2) for N wakeups.
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 */
72
Linus Torvalds1da177e2005-04-16 15:20:36 -070073#include <linux/slab.h>
74#include <linux/spinlock.h>
75#include <linux/init.h>
76#include <linux/proc_fs.h>
77#include <linux/time.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070078#include <linux/security.h>
79#include <linux/syscalls.h>
80#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080081#include <linux/capability.h>
Mike Waychison19b49462005-09-06 15:17:10 -070082#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070083#include <linux/rwsem.h>
Kirill Korotaeve3893532006-10-02 02:18:22 -070084#include <linux/nsproxy.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080085#include <linux/ipc_namespace.h>
Ingo Molnar84f001e2017-02-01 16:36:40 +010086#include <linux/sched/wake_q.h>
Ingo Molnar5f921ae2006-03-26 01:37:17 -080087
Paul McQuade7153e402014-06-06 14:37:37 -070088#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070089#include "util.h"
90
Manfred Spraule57940d2011-11-02 13:38:54 -070091
92/* One queue for each sleeping process in the system. */
93struct sem_queue {
Manfred Spraule57940d2011-11-02 13:38:54 -070094 struct list_head list; /* queue of pending operations */
95 struct task_struct *sleeper; /* this process */
96 struct sem_undo *undo; /* undo structure */
97 int pid; /* process id of requesting process */
98 int status; /* completion status of operation */
99 struct sembuf *sops; /* array of pending operations */
Manfred Sprauled247b72014-06-06 14:37:49 -0700100 struct sembuf *blocking; /* the operation that blocked */
Manfred Spraule57940d2011-11-02 13:38:54 -0700101 int nsops; /* number of operations */
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800102 bool alter; /* does *sops alter the array? */
103 bool dupsop; /* sops on more than one sem_num */
Manfred Spraule57940d2011-11-02 13:38:54 -0700104};
105
106/* Each task has a list of undo requests. They are executed automatically
107 * when the process exits.
108 */
109struct sem_undo {
110 struct list_head list_proc; /* per-process list: *
111 * all undos from one process
112 * rcu protected */
113 struct rcu_head rcu; /* rcu struct for sem_undo */
114 struct sem_undo_list *ulp; /* back ptr to sem_undo_list */
115 struct list_head list_id; /* per semaphore array list:
116 * all undos for one array */
117 int semid; /* semaphore set identifier */
118 short *semadj; /* array of adjustments */
119 /* one per semaphore */
120};
121
122/* sem_undo_list controls shared access to the list of sem_undo structures
123 * that may be shared among all a CLONE_SYSVSEM task group.
124 */
125struct sem_undo_list {
Elena Reshetovaf74370b2017-09-08 16:17:42 -0700126 refcount_t refcnt;
Manfred Spraule57940d2011-11-02 13:38:54 -0700127 spinlock_t lock;
128 struct list_head list_proc;
129};
130
131
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800132#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS])
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700134static int newary(struct ipc_namespace *, struct ipc_params *);
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800135static void freeary(struct ipc_namespace *, struct kern_ipc_perm *);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700137static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138#endif
139
140#define SEMMSL_FAST 256 /* 512 bytes on stack */
141#define SEMOPM_FAST 64 /* ~ 372 bytes on stack */
142
143/*
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800144 * Switching from the mode suitable for simple ops
145 * to the mode for complex ops is costly. Therefore:
146 * use some hysteresis
147 */
148#define USE_GLOBAL_LOCK_HYSTERESIS 10
149
150/*
Manfred Spraul758a6ba32013-07-08 16:01:26 -0700151 * Locking:
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700152 * a) global sem_lock() for read/write
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 * sem_undo.id_next,
Manfred Spraul758a6ba32013-07-08 16:01:26 -0700154 * sem_array.complex_count,
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700155 * sem_array.pending{_alter,_const},
156 * sem_array.sem_undo
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700157 *
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700158 * b) global or semaphore sem_lock() for read/write:
Manfred Spraul1a233952017-07-12 14:34:38 -0700159 * sem_array.sems[i].pending_{const,alter}:
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700160 *
161 * c) special:
162 * sem_undo_list.list_proc:
163 * * undo_list->lock for write
164 * * rcu for read
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800165 * use_global_lock:
166 * * global sem_lock() for write
167 * * either local or global sem_lock() for read.
168 *
169 * Memory ordering:
170 * Most ordering is enforced by using spin_lock() and spin_unlock().
171 * The special case is use_global_lock:
172 * Setting it from non-zero to 0 is a RELEASE, this is ensured by
173 * using smp_store_release().
174 * Testing if it is non-zero is an ACQUIRE, this is ensured by using
175 * smp_load_acquire().
176 * Setting it from 0 to non-zero must be ordered with regards to
177 * this smp_load_acquire(), this is guaranteed because the smp_load_acquire()
178 * is inside a spin_lock() and after a write from 0 to non-zero a
179 * spin_lock()+spin_unlock() is done.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 */
181
Kirill Korotaeve3893532006-10-02 02:18:22 -0700182#define sc_semmsl sem_ctls[0]
183#define sc_semmns sem_ctls[1]
184#define sc_semopm sem_ctls[2]
185#define sc_semmni sem_ctls[3]
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700187int sem_init_ns(struct ipc_namespace *ns)
Kirill Korotaeve3893532006-10-02 02:18:22 -0700188{
Kirill Korotaeve3893532006-10-02 02:18:22 -0700189 ns->sc_semmsl = SEMMSL;
190 ns->sc_semmns = SEMMNS;
191 ns->sc_semopm = SEMOPM;
192 ns->sc_semmni = SEMMNI;
193 ns->used_sems = 0;
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700194 return ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
Kirill Korotaeve3893532006-10-02 02:18:22 -0700195}
196
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800197#ifdef CONFIG_IPC_NS
Kirill Korotaeve3893532006-10-02 02:18:22 -0700198void sem_exit_ns(struct ipc_namespace *ns)
199{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800200 free_ipcs(ns, &sem_ids(ns), freeary);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800201 idr_destroy(&ns->ids[IPC_SEM_IDS].ipcs_idr);
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700202 rhashtable_destroy(&ns->ids[IPC_SEM_IDS].key_ht);
Kirill Korotaeve3893532006-10-02 02:18:22 -0700203}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800204#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700206int __init sem_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700208 const int err = sem_init_ns(&init_ipc_ns);
209
Mike Waychison19b49462005-09-06 15:17:10 -0700210 ipc_init_proc_interface("sysvipc/sem",
211 " key semid perms nsems uid gid cuid cgid otime ctime\n",
Kirill Korotaeve3893532006-10-02 02:18:22 -0700212 IPC_SEM_IDS, sysvipc_sem_proc_show);
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700213 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
Manfred Spraulf269f402013-07-08 16:01:24 -0700216/**
217 * unmerge_queues - unmerge queues, if possible.
218 * @sma: semaphore array
219 *
220 * The function unmerges the wait queues if complex_count is 0.
221 * It must be called prior to dropping the global semaphore array lock.
222 */
223static void unmerge_queues(struct sem_array *sma)
224{
225 struct sem_queue *q, *tq;
226
227 /* complex operations still around? */
228 if (sma->complex_count)
229 return;
230 /*
231 * We will switch back to simple mode.
232 * Move all pending operation back into the per-semaphore
233 * queues.
234 */
235 list_for_each_entry_safe(q, tq, &sma->pending_alter, list) {
236 struct sem *curr;
Manfred Spraul1a233952017-07-12 14:34:38 -0700237 curr = &sma->sems[q->sops[0].sem_num];
Manfred Spraulf269f402013-07-08 16:01:24 -0700238
239 list_add_tail(&q->list, &curr->pending_alter);
240 }
241 INIT_LIST_HEAD(&sma->pending_alter);
242}
243
244/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800245 * merge_queues - merge single semop queues into global queue
Manfred Spraulf269f402013-07-08 16:01:24 -0700246 * @sma: semaphore array
247 *
248 * This function merges all per-semaphore queues into the global queue.
249 * It is necessary to achieve FIFO ordering for the pending single-sop
250 * operations when a multi-semop operation must sleep.
251 * Only the alter operations must be moved, the const operations can stay.
252 */
253static void merge_queues(struct sem_array *sma)
254{
255 int i;
256 for (i = 0; i < sma->sem_nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700257 struct sem *sem = &sma->sems[i];
Manfred Spraulf269f402013-07-08 16:01:24 -0700258
259 list_splice_init(&sem->pending_alter, &sma->pending_alter);
260 }
261}
262
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700263static void sem_rcu_free(struct rcu_head *head)
264{
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700265 struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
266 struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700267
268 security_sem_free(sma);
Kees Cooke2029df2017-07-12 14:35:31 -0700269 kvfree(sma);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700270}
271
Nadia Derbey3e148c72007-10-18 23:40:54 -0700272/*
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700273 * Enter the mode suitable for non-simple operations:
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700274 * Caller must own sem_perm.lock.
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700275 */
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700276static void complexmode_enter(struct sem_array *sma)
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700277{
278 int i;
279 struct sem *sem;
280
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800281 if (sma->use_global_lock > 0) {
282 /*
283 * We are already in global lock mode.
284 * Nothing to do, just reset the
285 * counter until we return to simple mode.
286 */
287 sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
Manfred Spraul6d07b682013-09-30 13:45:06 -0700288 return;
289 }
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800290 sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700291
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700292 for (i = 0; i < sma->sem_nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700293 sem = &sma->sems[i];
Manfred Spraul27d7be12017-02-27 14:28:15 -0800294 spin_lock(&sem->lock);
295 spin_unlock(&sem->lock);
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700296 }
297}
298
299/*
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700300 * Try to leave the mode that disallows simple operations:
301 * Caller must own sem_perm.lock.
302 */
303static void complexmode_tryleave(struct sem_array *sma)
304{
305 if (sma->complex_count) {
306 /* Complex ops are sleeping.
307 * We must stay in complex mode
308 */
309 return;
310 }
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800311 if (sma->use_global_lock == 1) {
312 /*
313 * Immediately after setting use_global_lock to 0,
314 * a simple op can start. Thus: all memory writes
315 * performed by the current operation must be visible
316 * before we set use_global_lock to 0.
317 */
318 smp_store_release(&sma->use_global_lock, 0);
319 } else {
320 sma->use_global_lock--;
321 }
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700322}
323
324#define SEM_GLOBAL_LOCK (-1)
325/*
Rik van Riel6062a8d2013-04-30 19:15:44 -0700326 * If the request contains only one semaphore operation, and there are
327 * no complex transactions pending, lock only the semaphore involved.
328 * Otherwise, lock the entire semaphore array, since we either have
329 * multiple semaphores in our own semops, or we need to look at
330 * semaphores from other pending complex operations.
Rik van Riel6062a8d2013-04-30 19:15:44 -0700331 */
332static inline int sem_lock(struct sem_array *sma, struct sembuf *sops,
333 int nsops)
334{
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700335 struct sem *sem;
Rik van Riel6062a8d2013-04-30 19:15:44 -0700336
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700337 if (nsops != 1) {
338 /* Complex operation - acquire a full lock */
339 ipc_lock_object(&sma->sem_perm);
340
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700341 /* Prevent parallel simple ops */
342 complexmode_enter(sma);
343 return SEM_GLOBAL_LOCK;
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700344 }
345
346 /*
347 * Only one semaphore affected - try to optimize locking.
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700348 * Optimized locking is possible if no complex operation
349 * is either enqueued or processed right now.
350 *
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800351 * Both facts are tracked by use_global_mode.
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700352 */
Manfred Spraul1a233952017-07-12 14:34:38 -0700353 sem = &sma->sems[sops->sem_num];
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700354
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700355 /*
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800356 * Initial check for use_global_lock. Just an optimization,
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700357 * no locking, no memory barrier.
358 */
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800359 if (!sma->use_global_lock) {
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700360 /*
361 * It appears that no complex operation is around.
362 * Acquire the per-semaphore lock.
363 */
Rik van Riel6062a8d2013-04-30 19:15:44 -0700364 spin_lock(&sem->lock);
365
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800366 /* pairs with smp_store_release() */
367 if (!smp_load_acquire(&sma->use_global_lock)) {
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700368 /* fast path successful! */
369 return sops->sem_num;
Rik van Riel6062a8d2013-04-30 19:15:44 -0700370 }
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700371 spin_unlock(&sem->lock);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700372 }
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700373
374 /* slow path: acquire the full lock */
375 ipc_lock_object(&sma->sem_perm);
376
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800377 if (sma->use_global_lock == 0) {
378 /*
379 * The use_global_lock mode ended while we waited for
380 * sma->sem_perm.lock. Thus we must switch to locking
381 * with sem->lock.
382 * Unlike in the fast path, there is no need to recheck
383 * sma->use_global_lock after we have acquired sem->lock:
384 * We own sma->sem_perm.lock, thus use_global_lock cannot
385 * change.
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700386 */
387 spin_lock(&sem->lock);
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800388
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700389 ipc_unlock_object(&sma->sem_perm);
390 return sops->sem_num;
391 } else {
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800392 /*
393 * Not a false alarm, thus continue to use the global lock
394 * mode. No need for complexmode_enter(), this was done by
395 * the caller that has set use_global_mode to non-zero.
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700396 */
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700397 return SEM_GLOBAL_LOCK;
Manfred Spraul5e9d5272013-09-30 13:45:04 -0700398 }
Rik van Riel6062a8d2013-04-30 19:15:44 -0700399}
400
401static inline void sem_unlock(struct sem_array *sma, int locknum)
402{
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700403 if (locknum == SEM_GLOBAL_LOCK) {
Manfred Spraulf269f402013-07-08 16:01:24 -0700404 unmerge_queues(sma);
Manfred Spraul5864a2f2016-10-11 13:54:50 -0700405 complexmode_tryleave(sma);
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700406 ipc_unlock_object(&sma->sem_perm);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700407 } else {
Manfred Spraul1a233952017-07-12 14:34:38 -0700408 struct sem *sem = &sma->sems[locknum];
Rik van Riel6062a8d2013-04-30 19:15:44 -0700409 spin_unlock(&sem->lock);
410 }
Rik van Riel6062a8d2013-04-30 19:15:44 -0700411}
412
413/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700414 * sem_lock_(check_) routines are called in the paths where the rwsem
Nadia Derbey3e148c72007-10-18 23:40:54 -0700415 * is not held.
Linus Torvalds321310c2013-05-04 10:47:57 -0700416 *
417 * The caller holds the RCU read lock.
Nadia Derbey3e148c72007-10-18 23:40:54 -0700418 */
Davidlohr Bueso16df3672013-04-30 19:15:29 -0700419static inline struct sem_array *sem_obtain_object(struct ipc_namespace *ns, int id)
420{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700421 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&sem_ids(ns), id);
Davidlohr Bueso16df3672013-04-30 19:15:29 -0700422
423 if (IS_ERR(ipcp))
424 return ERR_CAST(ipcp);
425
426 return container_of(ipcp, struct sem_array, sem_perm);
427}
428
Davidlohr Bueso16df3672013-04-30 19:15:29 -0700429static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns,
430 int id)
431{
432 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&sem_ids(ns), id);
433
434 if (IS_ERR(ipcp))
435 return ERR_CAST(ipcp);
Pierre Peifferb1ed88b2008-02-06 01:36:23 -0800436
Nadia Derbey03f02c72007-10-18 23:40:51 -0700437 return container_of(ipcp, struct sem_array, sem_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700438}
439
Pierre Peiffer6ff37972008-04-29 01:00:46 -0700440static inline void sem_lock_and_putref(struct sem_array *sma)
441{
Rik van Riel6062a8d2013-04-30 19:15:44 -0700442 sem_lock(sma, NULL, -1);
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700443 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Pierre Peiffer6ff37972008-04-29 01:00:46 -0700444}
445
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700446static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
447{
448 ipc_rmid(&sem_ids(ns), &s->sem_perm);
449}
450
Kees Cook101ede02017-07-12 14:35:02 -0700451static struct sem_array *sem_alloc(size_t nsems)
452{
453 struct sem_array *sma;
454 size_t size;
455
456 if (nsems > (INT_MAX - sizeof(*sma)) / sizeof(sma->sems[0]))
457 return NULL;
458
459 size = sizeof(*sma) + nsems * sizeof(sma->sems[0]);
460 sma = kvmalloc(size, GFP_KERNEL);
461 if (unlikely(!sma))
462 return NULL;
463
464 memset(sma, 0, size);
Kees Cook101ede02017-07-12 14:35:02 -0700465
466 return sma;
467}
468
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700469/**
470 * newary - Create a new semaphore set
471 * @ns: namespace
472 * @params: ptr to the structure that contains key, semflg and nsems
473 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700474 * Called with sem_ids.rwsem held (as a writer)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700475 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700476static int newary(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 int retval;
479 struct sem_array *sma;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700480 key_t key = params->key;
481 int nsems = params->u.nsems;
482 int semflg = params->flg;
Manfred Spraulb97e8202009-12-15 16:47:32 -0800483 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485 if (!nsems)
486 return -EINVAL;
Kirill Korotaeve3893532006-10-02 02:18:22 -0700487 if (ns->used_sems + nsems > ns->sc_semmns)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 return -ENOSPC;
489
Kees Cook101ede02017-07-12 14:35:02 -0700490 sma = sem_alloc(nsems);
Davidlohr Bueso3ab08fe2014-01-27 17:07:06 -0800491 if (!sma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 return -ENOMEM;
Davidlohr Bueso3ab08fe2014-01-27 17:07:06 -0800493
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 sma->sem_perm.mode = (semflg & S_IRWXUGO);
495 sma->sem_perm.key = key;
496
497 sma->sem_perm.security = NULL;
498 retval = security_sem_alloc(sma);
499 if (retval) {
Kees Cooke2029df2017-07-12 14:35:31 -0700500 kvfree(sma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 return retval;
502 }
503
Rik van Riel6062a8d2013-04-30 19:15:44 -0700504 for (i = 0; i < nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700505 INIT_LIST_HEAD(&sma->sems[i].pending_alter);
506 INIT_LIST_HEAD(&sma->sems[i].pending_const);
507 spin_lock_init(&sma->sems[i].lock);
Rik van Riel6062a8d2013-04-30 19:15:44 -0700508 }
Manfred Spraulb97e8202009-12-15 16:47:32 -0800509
510 sma->complex_count = 0;
Manfred Spraul9de5ab82017-02-27 14:28:18 -0800511 sma->use_global_lock = USE_GLOBAL_LOCK_HYSTERESIS;
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700512 INIT_LIST_HEAD(&sma->pending_alter);
513 INIT_LIST_HEAD(&sma->pending_const);
Manfred Spraul4daa28f2008-07-25 01:48:04 -0700514 INIT_LIST_HEAD(&sma->list_id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 sma->sem_nsems = nsems;
Deepa Dinamanie54d02b2017-08-02 19:51:13 -0700516 sma->sem_ctime = ktime_get_real_seconds();
Manfred Spraule8577d12014-12-02 15:59:34 -0800517
Manfred Spraul2ec55f82017-07-12 14:35:13 -0700518 retval = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
519 if (retval < 0) {
520 call_rcu(&sma->sem_perm.rcu, sem_rcu_free);
521 return retval;
Manfred Spraule8577d12014-12-02 15:59:34 -0800522 }
523 ns->used_sems += nsems;
524
Rik van Riel6062a8d2013-04-30 19:15:44 -0700525 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -0700526 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700528 return sma->sem_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529}
530
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700531
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700532/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700533 * Called with sem_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700534 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700535static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700537 struct sem_array *sma;
538
539 sma = container_of(ipcp, struct sem_array, sem_perm);
540 return security_sem_associate(sma, semflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700541}
542
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700543/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700544 * Called with sem_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700545 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700546static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
547 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700548{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700549 struct sem_array *sma;
550
551 sma = container_of(ipcp, struct sem_array, sem_perm);
552 if (params->u.nsems > sma->sem_nsems)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700553 return -EINVAL;
554
555 return 0;
556}
557
Heiko Carstensd5460c92009-01-14 14:14:27 +0100558SYSCALL_DEFINE3(semget, key_t, key, int, nsems, int, semflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700559{
Kirill Korotaeve3893532006-10-02 02:18:22 -0700560 struct ipc_namespace *ns;
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700561 static const struct ipc_ops sem_ops = {
562 .getnew = newary,
563 .associate = sem_security,
564 .more_checks = sem_more_checks,
565 };
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700566 struct ipc_params sem_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567
Kirill Korotaeve3893532006-10-02 02:18:22 -0700568 ns = current->nsproxy->ipc_ns;
569
570 if (nsems < 0 || nsems > ns->sc_semmsl)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 return -EINVAL;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700572
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700573 sem_params.key = key;
574 sem_params.flg = semflg;
575 sem_params.u.nsems = nsems;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700576
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700577 return ipcget(ns, &sem_ids(ns), &sem_ops, &sem_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578}
579
Petr Mladek78f50092014-01-27 17:07:00 -0800580/**
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800581 * perform_atomic_semop[_slow] - Attempt to perform semaphore
582 * operations on a given array.
Manfred Spraul758a6ba32013-07-08 16:01:26 -0700583 * @sma: semaphore array
Manfred Sprauld198cd62014-06-06 14:37:49 -0700584 * @q: struct sem_queue that describes the operation
Manfred Spraul758a6ba32013-07-08 16:01:26 -0700585 *
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800586 * Caller blocking are as follows, based the value
587 * indicated by the semaphore operation (sem_op):
588 *
589 * (1) >0 never blocks.
590 * (2) 0 (wait-for-zero operation): semval is non-zero.
591 * (3) <0 attempting to decrement semval to a value smaller than zero.
592 *
Manfred Spraul758a6ba32013-07-08 16:01:26 -0700593 * Returns 0 if the operation was possible.
594 * Returns 1 if the operation is impossible, the caller must sleep.
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800595 * Returns <0 for error codes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 */
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800597static int perform_atomic_semop_slow(struct sem_array *sma, struct sem_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598{
Manfred Sprauld198cd62014-06-06 14:37:49 -0700599 int result, sem_op, nsops, pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 struct sembuf *sop;
Manfred Spraul239521f2014-01-27 17:07:04 -0800601 struct sem *curr;
Manfred Sprauld198cd62014-06-06 14:37:49 -0700602 struct sembuf *sops;
603 struct sem_undo *un;
604
605 sops = q->sops;
606 nsops = q->nsops;
607 un = q->undo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 for (sop = sops; sop < sops + nsops; sop++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700610 curr = &sma->sems[sop->sem_num];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 sem_op = sop->sem_op;
612 result = curr->semval;
Petr Mladek78f50092014-01-27 17:07:00 -0800613
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 if (!sem_op && result)
615 goto would_block;
616
617 result += sem_op;
618 if (result < 0)
619 goto would_block;
620 if (result > SEMVMX)
621 goto out_of_range;
Petr Mladek78f50092014-01-27 17:07:00 -0800622
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 if (sop->sem_flg & SEM_UNDO) {
624 int undo = un->semadj[sop->sem_num] - sem_op;
Petr Mladek78f50092014-01-27 17:07:00 -0800625 /* Exceeding the undo range is an error. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 if (undo < (-SEMAEM - 1) || undo > SEMAEM)
627 goto out_of_range;
Petr Mladek78f50092014-01-27 17:07:00 -0800628 un->semadj[sop->sem_num] = undo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 }
Petr Mladek78f50092014-01-27 17:07:00 -0800630
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 curr->semval = result;
632 }
633
634 sop--;
Manfred Sprauld198cd62014-06-06 14:37:49 -0700635 pid = q->pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 while (sop >= sops) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700637 sma->sems[sop->sem_num].sempid = pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 sop--;
639 }
Petr Mladek78f50092014-01-27 17:07:00 -0800640
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 return 0;
642
643out_of_range:
644 result = -ERANGE;
645 goto undo;
646
647would_block:
Manfred Sprauled247b72014-06-06 14:37:49 -0700648 q->blocking = sop;
649
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (sop->sem_flg & IPC_NOWAIT)
651 result = -EAGAIN;
652 else
653 result = 1;
654
655undo:
656 sop--;
657 while (sop >= sops) {
Petr Mladek78f50092014-01-27 17:07:00 -0800658 sem_op = sop->sem_op;
Manfred Spraul1a233952017-07-12 14:34:38 -0700659 sma->sems[sop->sem_num].semval -= sem_op;
Petr Mladek78f50092014-01-27 17:07:00 -0800660 if (sop->sem_flg & SEM_UNDO)
661 un->semadj[sop->sem_num] += sem_op;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 sop--;
663 }
664
665 return result;
666}
667
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800668static int perform_atomic_semop(struct sem_array *sma, struct sem_queue *q)
669{
670 int result, sem_op, nsops;
671 struct sembuf *sop;
672 struct sem *curr;
673 struct sembuf *sops;
674 struct sem_undo *un;
675
676 sops = q->sops;
677 nsops = q->nsops;
678 un = q->undo;
679
680 if (unlikely(q->dupsop))
681 return perform_atomic_semop_slow(sma, q);
682
683 /*
684 * We scan the semaphore set twice, first to ensure that the entire
685 * operation can succeed, therefore avoiding any pointless writes
686 * to shared memory and having to undo such changes in order to block
687 * until the operations can go through.
688 */
689 for (sop = sops; sop < sops + nsops; sop++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700690 curr = &sma->sems[sop->sem_num];
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800691 sem_op = sop->sem_op;
692 result = curr->semval;
693
694 if (!sem_op && result)
695 goto would_block; /* wait-for-zero */
696
697 result += sem_op;
698 if (result < 0)
699 goto would_block;
700
701 if (result > SEMVMX)
702 return -ERANGE;
703
704 if (sop->sem_flg & SEM_UNDO) {
705 int undo = un->semadj[sop->sem_num] - sem_op;
706
707 /* Exceeding the undo range is an error. */
708 if (undo < (-SEMAEM - 1) || undo > SEMAEM)
709 return -ERANGE;
710 }
711 }
712
713 for (sop = sops; sop < sops + nsops; sop++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700714 curr = &sma->sems[sop->sem_num];
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -0800715 sem_op = sop->sem_op;
716 result = curr->semval;
717
718 if (sop->sem_flg & SEM_UNDO) {
719 int undo = un->semadj[sop->sem_num] - sem_op;
720
721 un->semadj[sop->sem_num] = undo;
722 }
723 curr->semval += sem_op;
724 curr->sempid = q->pid;
725 }
726
727 return 0;
728
729would_block:
730 q->blocking = sop;
731 return sop->sem_flg & IPC_NOWAIT ? -EAGAIN : 1;
732}
733
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800734static inline void wake_up_sem_queue_prepare(struct sem_queue *q, int error,
735 struct wake_q_head *wake_q)
Nick Piggind4212092009-12-15 16:47:30 -0800736{
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800737 wake_q_add(wake_q, q->sleeper);
738 /*
739 * Rely on the above implicit barrier, such that we can
740 * ensure that we hold reference to the task before setting
741 * q->status. Otherwise we could race with do_exit if the
742 * task is awoken by an external event before calling
743 * wake_up_process().
744 */
745 WRITE_ONCE(q->status, error);
Nick Piggind4212092009-12-15 16:47:30 -0800746}
747
Manfred Spraulb97e8202009-12-15 16:47:32 -0800748static void unlink_queue(struct sem_array *sma, struct sem_queue *q)
749{
750 list_del(&q->list);
Rik van Riel9f1bc2c92013-04-30 19:15:39 -0700751 if (q->nsops > 1)
Manfred Spraulb97e8202009-12-15 16:47:32 -0800752 sma->complex_count--;
753}
754
Manfred Spraulfd5db422010-05-26 14:43:40 -0700755/** check_restart(sma, q)
756 * @sma: semaphore array
757 * @q: the operation that just completed
758 *
759 * update_queue is O(N^2) when it restarts scanning the whole queue of
760 * waiting operations. Therefore this function checks if the restart is
761 * really necessary. It is called after a previously waiting operation
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700762 * modified the array.
763 * Note that wait-for-zero operations are handled without restart.
Manfred Spraulfd5db422010-05-26 14:43:40 -0700764 */
Davidlohr Bueso4663d3e2016-12-14 15:06:40 -0800765static inline int check_restart(struct sem_array *sma, struct sem_queue *q)
Manfred Spraulfd5db422010-05-26 14:43:40 -0700766{
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700767 /* pending complex alter operations are too difficult to analyse */
768 if (!list_empty(&sma->pending_alter))
Manfred Spraulfd5db422010-05-26 14:43:40 -0700769 return 1;
770
771 /* we were a sleeping complex operation. Too difficult */
772 if (q->nsops > 1)
773 return 1;
774
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700775 /* It is impossible that someone waits for the new value:
776 * - complex operations always restart.
777 * - wait-for-zero are handled seperately.
778 * - q is a previously sleeping simple operation that
779 * altered the array. It must be a decrement, because
780 * simple increments never sleep.
781 * - If there are older (higher priority) decrements
782 * in the queue, then they have observed the original
783 * semval value and couldn't proceed. The operation
784 * decremented to value - thus they won't proceed either.
785 */
786 return 0;
787}
Manfred Spraulfd5db422010-05-26 14:43:40 -0700788
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700789/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800790 * wake_const_ops - wake up non-alter tasks
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700791 * @sma: semaphore array.
792 * @semnum: semaphore that was modified.
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800793 * @wake_q: lockless wake-queue head.
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700794 *
795 * wake_const_ops must be called after a semaphore in a semaphore array
796 * was set to 0. If complex const operations are pending, wake_const_ops must
797 * be called with semnum = -1, as well as with the number of each modified
798 * semaphore.
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800799 * The tasks that must be woken up are added to @wake_q. The return code
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700800 * is stored in q->pid.
801 * The function returns 1 if at least one operation was completed successfully.
802 */
803static int wake_const_ops(struct sem_array *sma, int semnum,
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800804 struct wake_q_head *wake_q)
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700805{
Davidlohr Buesof150f022016-12-14 15:06:43 -0800806 struct sem_queue *q, *tmp;
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700807 struct list_head *pending_list;
808 int semop_completed = 0;
Manfred Spraulfd5db422010-05-26 14:43:40 -0700809
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700810 if (semnum == -1)
811 pending_list = &sma->pending_const;
812 else
Manfred Spraul1a233952017-07-12 14:34:38 -0700813 pending_list = &sma->sems[semnum].pending_const;
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700814
Davidlohr Buesof150f022016-12-14 15:06:43 -0800815 list_for_each_entry_safe(q, tmp, pending_list, list) {
816 int error = perform_atomic_semop(sma, q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700817
Davidlohr Buesof150f022016-12-14 15:06:43 -0800818 if (error > 0)
819 continue;
820 /* operation completed, remove from queue & wakeup */
821 unlink_queue(sma, q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700822
Davidlohr Buesof150f022016-12-14 15:06:43 -0800823 wake_up_sem_queue_prepare(q, error, wake_q);
824 if (error == 0)
825 semop_completed = 1;
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700826 }
Davidlohr Buesof150f022016-12-14 15:06:43 -0800827
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700828 return semop_completed;
829}
830
831/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800832 * do_smart_wakeup_zero - wakeup all wait for zero tasks
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700833 * @sma: semaphore array
834 * @sops: operations that were performed
835 * @nsops: number of operations
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800836 * @wake_q: lockless wake-queue head
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700837 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800838 * Checks all required queue for wait-for-zero operations, based
839 * on the actual changes that were performed on the semaphore array.
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700840 * The function returns 1 if at least one operation was completed successfully.
841 */
842static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops,
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800843 int nsops, struct wake_q_head *wake_q)
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700844{
845 int i;
846 int semop_completed = 0;
847 int got_zero = 0;
848
849 /* first: the per-semaphore queues, if known */
850 if (sops) {
851 for (i = 0; i < nsops; i++) {
852 int num = sops[i].sem_num;
853
Manfred Spraul1a233952017-07-12 14:34:38 -0700854 if (sma->sems[num].semval == 0) {
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700855 got_zero = 1;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800856 semop_completed |= wake_const_ops(sma, num, wake_q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700857 }
858 }
859 } else {
860 /*
861 * No sops means modified semaphores not known.
862 * Assume all were changed.
Manfred Spraulfd5db422010-05-26 14:43:40 -0700863 */
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700864 for (i = 0; i < sma->sem_nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700865 if (sma->sems[i].semval == 0) {
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700866 got_zero = 1;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800867 semop_completed |= wake_const_ops(sma, i, wake_q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700868 }
869 }
Manfred Spraulfd5db422010-05-26 14:43:40 -0700870 }
871 /*
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700872 * If one of the modified semaphores got 0,
873 * then check the global queue, too.
Manfred Spraulfd5db422010-05-26 14:43:40 -0700874 */
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700875 if (got_zero)
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800876 semop_completed |= wake_const_ops(sma, -1, wake_q);
Manfred Spraulfd5db422010-05-26 14:43:40 -0700877
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700878 return semop_completed;
Manfred Spraulfd5db422010-05-26 14:43:40 -0700879}
880
Manfred Spraul636c6be2009-12-15 16:47:33 -0800881
882/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800883 * update_queue - look for tasks that can be completed.
Manfred Spraul636c6be2009-12-15 16:47:33 -0800884 * @sma: semaphore array.
885 * @semnum: semaphore that was modified.
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800886 * @wake_q: lockless wake-queue head.
Manfred Spraul636c6be2009-12-15 16:47:33 -0800887 *
888 * update_queue must be called after a semaphore in a semaphore array
Rik van Riel9f1bc2c92013-04-30 19:15:39 -0700889 * was modified. If multiple semaphores were modified, update_queue must
890 * be called with semnum = -1, as well as with the number of each modified
891 * semaphore.
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800892 * The tasks that must be woken up are added to @wake_q. The return code
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700893 * is stored in q->pid.
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700894 * The function internally checks if const operations can now succeed.
895 *
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700896 * The function return 1 if at least one semop was completed successfully.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 */
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800898static int update_queue(struct sem_array *sma, int semnum, struct wake_q_head *wake_q)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899{
Davidlohr Buesof150f022016-12-14 15:06:43 -0800900 struct sem_queue *q, *tmp;
Manfred Spraul636c6be2009-12-15 16:47:33 -0800901 struct list_head *pending_list;
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700902 int semop_completed = 0;
Manfred Spraul636c6be2009-12-15 16:47:33 -0800903
Rik van Riel9f1bc2c92013-04-30 19:15:39 -0700904 if (semnum == -1)
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700905 pending_list = &sma->pending_alter;
Rik van Riel9f1bc2c92013-04-30 19:15:39 -0700906 else
Manfred Spraul1a233952017-07-12 14:34:38 -0700907 pending_list = &sma->sems[semnum].pending_alter;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908
Nick Piggin9cad2002009-12-15 16:47:29 -0800909again:
Davidlohr Buesof150f022016-12-14 15:06:43 -0800910 list_for_each_entry_safe(q, tmp, pending_list, list) {
Manfred Spraulfd5db422010-05-26 14:43:40 -0700911 int error, restart;
Manfred Spraul636c6be2009-12-15 16:47:33 -0800912
Manfred Sprauld987f8b2009-12-15 16:47:34 -0800913 /* If we are scanning the single sop, per-semaphore list of
914 * one semaphore and that semaphore is 0, then it is not
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700915 * necessary to scan further: simple increments
Manfred Sprauld987f8b2009-12-15 16:47:34 -0800916 * that affect only one entry succeed immediately and cannot
917 * be in the per semaphore pending queue, and decrements
918 * cannot be successful if the value is already 0.
919 */
Manfred Spraul1a233952017-07-12 14:34:38 -0700920 if (semnum != -1 && sma->sems[semnum].semval == 0)
Manfred Sprauld987f8b2009-12-15 16:47:34 -0800921 break;
922
Manfred Sprauld198cd62014-06-06 14:37:49 -0700923 error = perform_atomic_semop(sma, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924
925 /* Does q->sleeper still need to sleep? */
Nick Piggin9cad2002009-12-15 16:47:29 -0800926 if (error > 0)
927 continue;
Manfred Spraula1193f82008-07-25 01:48:06 -0700928
Manfred Spraulb97e8202009-12-15 16:47:32 -0800929 unlink_queue(sma, q);
Manfred Spraula1193f82008-07-25 01:48:06 -0700930
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700931 if (error) {
Manfred Spraulfd5db422010-05-26 14:43:40 -0700932 restart = 0;
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700933 } else {
934 semop_completed = 1;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800935 do_smart_wakeup_zero(sma, q->sops, q->nsops, wake_q);
Manfred Spraulfd5db422010-05-26 14:43:40 -0700936 restart = check_restart(sma, q);
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700937 }
Manfred Spraulfd5db422010-05-26 14:43:40 -0700938
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800939 wake_up_sem_queue_prepare(q, error, wake_q);
Manfred Spraulfd5db422010-05-26 14:43:40 -0700940 if (restart)
Nick Piggin9cad2002009-12-15 16:47:29 -0800941 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 }
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700943 return semop_completed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944}
945
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700946/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800947 * set_semotime - set sem_otime
Manfred Spraul0e8c6652013-09-30 13:45:25 -0700948 * @sma: semaphore array
949 * @sops: operations that modified the array, may be NULL
950 *
951 * sem_otime is replicated to avoid cache line trashing.
952 * This function sets one instance to the current time.
953 */
954static void set_semotime(struct sem_array *sma, struct sembuf *sops)
955{
956 if (sops == NULL) {
Manfred Spraul1a233952017-07-12 14:34:38 -0700957 sma->sems[0].sem_otime = get_seconds();
Manfred Spraul0e8c6652013-09-30 13:45:25 -0700958 } else {
Manfred Spraul1a233952017-07-12 14:34:38 -0700959 sma->sems[sops[0].sem_num].sem_otime =
Manfred Spraul0e8c6652013-09-30 13:45:25 -0700960 get_seconds();
961 }
962}
963
964/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800965 * do_smart_update - optimized update_queue
Manfred Spraulfd5db422010-05-26 14:43:40 -0700966 * @sma: semaphore array
967 * @sops: operations that were performed
968 * @nsops: number of operations
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700969 * @otime: force setting otime
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800970 * @wake_q: lockless wake-queue head
Manfred Spraulfd5db422010-05-26 14:43:40 -0700971 *
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700972 * do_smart_update() does the required calls to update_queue and wakeup_zero,
973 * based on the actual changes that were performed on the semaphore array.
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700974 * Note that the function does not do the actual wake-up: the caller is
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800975 * responsible for calling wake_up_q().
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700976 * It is safe to perform this call after dropping all locks.
Manfred Spraulfd5db422010-05-26 14:43:40 -0700977 */
Manfred Spraul0a2b9d42010-05-26 14:43:41 -0700978static void do_smart_update(struct sem_array *sma, struct sembuf *sops, int nsops,
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800979 int otime, struct wake_q_head *wake_q)
Manfred Spraulfd5db422010-05-26 14:43:40 -0700980{
981 int i;
982
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800983 otime |= do_smart_wakeup_zero(sma, sops, nsops, wake_q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -0700984
Manfred Spraulf269f402013-07-08 16:01:24 -0700985 if (!list_empty(&sma->pending_alter)) {
986 /* semaphore array uses the global queue - just process it. */
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800987 otime |= update_queue(sma, -1, wake_q);
Manfred Spraulf269f402013-07-08 16:01:24 -0700988 } else {
989 if (!sops) {
990 /*
991 * No sops, thus the modified semaphores are not
992 * known. Check all.
993 */
994 for (i = 0; i < sma->sem_nsems; i++)
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -0800995 otime |= update_queue(sma, i, wake_q);
Manfred Spraulf269f402013-07-08 16:01:24 -0700996 } else {
997 /*
998 * Check the semaphores that were increased:
999 * - No complex ops, thus all sleeping ops are
1000 * decrease.
1001 * - if we decreased the value, then any sleeping
1002 * semaphore ops wont be able to run: If the
1003 * previous value was too small, then the new
1004 * value will be too small, too.
1005 */
1006 for (i = 0; i < nsops; i++) {
1007 if (sops[i].sem_op > 0) {
1008 otime |= update_queue(sma,
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001009 sops[i].sem_num, wake_q);
Manfred Spraulf269f402013-07-08 16:01:24 -07001010 }
Manfred Spraulab465df2013-05-26 11:08:52 +02001011 }
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07001012 }
Manfred Spraulfd5db422010-05-26 14:43:40 -07001013 }
Manfred Spraul0e8c6652013-09-30 13:45:25 -07001014 if (otime)
1015 set_semotime(sma, sops);
Manfred Spraulfd5db422010-05-26 14:43:40 -07001016}
1017
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001018/*
Manfred Spraulb220c572014-06-06 14:37:51 -07001019 * check_qop: Test if a queued operation sleeps on the semaphore semnum
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001020 */
1021static int check_qop(struct sem_array *sma, int semnum, struct sem_queue *q,
1022 bool count_zero)
1023{
Manfred Spraulb220c572014-06-06 14:37:51 -07001024 struct sembuf *sop = q->blocking;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001025
Manfred Spraul9b44ee22014-06-06 14:37:52 -07001026 /*
1027 * Linux always (since 0.99.10) reported a task as sleeping on all
1028 * semaphores. This violates SUS, therefore it was changed to the
1029 * standard compliant behavior.
1030 * Give the administrators a chance to notice that an application
1031 * might misbehave because it relies on the Linux behavior.
1032 */
1033 pr_info_once("semctl(GETNCNT/GETZCNT) is since 3.16 Single Unix Specification compliant.\n"
1034 "The task %s (%d) triggered the difference, watch for misbehavior.\n",
1035 current->comm, task_pid_nr(current));
1036
Manfred Spraulb220c572014-06-06 14:37:51 -07001037 if (sop->sem_num != semnum)
1038 return 0;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001039
Manfred Spraulb220c572014-06-06 14:37:51 -07001040 if (count_zero && sop->sem_op == 0)
1041 return 1;
1042 if (!count_zero && sop->sem_op < 0)
1043 return 1;
1044
1045 return 0;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001046}
1047
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048/* The following counts are associated to each semaphore:
1049 * semncnt number of tasks waiting on semval being nonzero
1050 * semzcnt number of tasks waiting on semval being zero
Manfred Spraulb220c572014-06-06 14:37:51 -07001051 *
1052 * Per definition, a task waits only on the semaphore of the first semop
1053 * that cannot proceed, even if additional operation would block, too.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 */
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001055static int count_semcnt(struct sem_array *sma, ushort semnum,
1056 bool count_zero)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057{
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001058 struct list_head *l;
Manfred Spraul239521f2014-01-27 17:07:04 -08001059 struct sem_queue *q;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001060 int semcnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001062 semcnt = 0;
1063 /* First: check the simple operations. They are easy to evaluate */
1064 if (count_zero)
Manfred Spraul1a233952017-07-12 14:34:38 -07001065 l = &sma->sems[semnum].pending_const;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001066 else
Manfred Spraul1a233952017-07-12 14:34:38 -07001067 l = &sma->sems[semnum].pending_alter;
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001068
1069 list_for_each_entry(q, l, list) {
1070 /* all task on a per-semaphore list sleep on exactly
1071 * that semaphore
1072 */
1073 semcnt++;
Rik van Rielde2657f2013-05-09 16:59:59 -04001074 }
1075
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001076 /* Then: check the complex operations. */
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07001077 list_for_each_entry(q, &sma->pending_alter, list) {
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001078 semcnt += check_qop(sma, semnum, q, count_zero);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079 }
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001080 if (count_zero) {
1081 list_for_each_entry(q, &sma->pending_const, list) {
1082 semcnt += check_qop(sma, semnum, q, count_zero);
1083 }
Rik van Rielebc2e5e2013-05-09 16:53:28 -04001084 }
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001085 return semcnt;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086}
1087
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001088/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked
1089 * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem
Nadia Derbey3e148c72007-10-18 23:40:54 -07001090 * remains locked on exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -08001092static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093{
Manfred Spraul380af1b2008-07-25 01:48:06 -07001094 struct sem_undo *un, *tu;
1095 struct sem_queue *q, *tq;
Pierre Peiffer01b8b072008-02-08 04:18:57 -08001096 struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07001097 int i;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001098 DEFINE_WAKE_Q(wake_q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099
Manfred Spraul380af1b2008-07-25 01:48:06 -07001100 /* Free the existing undo structures for this semaphore set. */
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -07001101 ipc_assert_locked_object(&sma->sem_perm);
Manfred Spraul380af1b2008-07-25 01:48:06 -07001102 list_for_each_entry_safe(un, tu, &sma->list_id, list_id) {
1103 list_del(&un->list_id);
1104 spin_lock(&un->ulp->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 un->semid = -1;
Manfred Spraul380af1b2008-07-25 01:48:06 -07001106 list_del_rcu(&un->list_proc);
1107 spin_unlock(&un->ulp->lock);
Lai Jiangshan693a8b62011-03-18 12:09:35 +08001108 kfree_rcu(un, rcu);
Manfred Spraul380af1b2008-07-25 01:48:06 -07001109 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110
1111 /* Wake up all pending processes and let them fail with EIDRM. */
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07001112 list_for_each_entry_safe(q, tq, &sma->pending_const, list) {
1113 unlink_queue(sma, q);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001114 wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07001115 }
1116
1117 list_for_each_entry_safe(q, tq, &sma->pending_alter, list) {
Manfred Spraulb97e8202009-12-15 16:47:32 -08001118 unlink_queue(sma, q);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001119 wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 }
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07001121 for (i = 0; i < sma->sem_nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -07001122 struct sem *sem = &sma->sems[i];
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07001123 list_for_each_entry_safe(q, tq, &sem->pending_const, list) {
1124 unlink_queue(sma, q);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001125 wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07001126 }
1127 list_for_each_entry_safe(q, tq, &sem->pending_alter, list) {
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07001128 unlink_queue(sma, q);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001129 wake_up_sem_queue_prepare(q, -EIDRM, &wake_q);
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07001130 }
1131 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132
Nadia Derbey7ca7e562007-10-18 23:40:48 -07001133 /* Remove the semaphore set from the IDR */
1134 sem_rmid(ns, sma);
Rik van Riel6062a8d2013-04-30 19:15:44 -07001135 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001136 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001138 wake_up_q(&wake_q);
Kirill Korotaeve3893532006-10-02 02:18:22 -07001139 ns->used_sems -= sma->sem_nsems;
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001140 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141}
1142
1143static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version)
1144{
Manfred Spraul239521f2014-01-27 17:07:04 -08001145 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146 case IPC_64:
1147 return copy_to_user(buf, in, sizeof(*in));
1148 case IPC_OLD:
1149 {
1150 struct semid_ds out;
1151
Dan Rosenberg982f7c22010-09-30 15:15:31 -07001152 memset(&out, 0, sizeof(out));
1153
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 ipc64_perm_to_ipc_perm(&in->sem_perm, &out.sem_perm);
1155
1156 out.sem_otime = in->sem_otime;
1157 out.sem_ctime = in->sem_ctime;
1158 out.sem_nsems = in->sem_nsems;
1159
1160 return copy_to_user(buf, &out, sizeof(out));
1161 }
1162 default:
1163 return -EINVAL;
1164 }
1165}
1166
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001167static time64_t get_semotime(struct sem_array *sma)
Manfred Sprauld12e1e52013-07-08 16:01:25 -07001168{
1169 int i;
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001170 time64_t res;
Manfred Sprauld12e1e52013-07-08 16:01:25 -07001171
Manfred Spraul1a233952017-07-12 14:34:38 -07001172 res = sma->sems[0].sem_otime;
Manfred Sprauld12e1e52013-07-08 16:01:25 -07001173 for (i = 1; i < sma->sem_nsems; i++) {
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001174 time64_t to = sma->sems[i].sem_otime;
Manfred Sprauld12e1e52013-07-08 16:01:25 -07001175
1176 if (to > res)
1177 res = to;
1178 }
1179 return res;
1180}
1181
Al Viro45a4a642017-07-09 09:11:00 -04001182static int semctl_stat(struct ipc_namespace *ns, int semid,
1183 int cmd, struct semid64_ds *semid64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 struct sem_array *sma;
Al Viro45a4a642017-07-09 09:11:00 -04001186 int id = 0;
1187 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001188
Al Viro45a4a642017-07-09 09:11:00 -04001189 memset(semid64, 0, sizeof(*semid64));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
Al Viro45a4a642017-07-09 09:11:00 -04001191 rcu_read_lock();
1192 if (cmd == SEM_STAT) {
1193 sma = sem_obtain_object(ns, semid);
1194 if (IS_ERR(sma)) {
1195 err = PTR_ERR(sma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001196 goto out_unlock;
Al Viro45a4a642017-07-09 09:11:00 -04001197 }
1198 id = sma->sem_perm.id;
1199 } else {
1200 sma = sem_obtain_object_check(ns, semid);
1201 if (IS_ERR(sma)) {
1202 err = PTR_ERR(sma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 goto out_unlock;
Al Viro45a4a642017-07-09 09:11:00 -04001204 }
1205 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206
Al Viro45a4a642017-07-09 09:11:00 -04001207 err = -EACCES;
1208 if (ipcperms(ns, &sma->sem_perm, S_IRUGO))
1209 goto out_unlock;
1210
1211 err = security_sem_semctl(sma, cmd);
1212 if (err)
1213 goto out_unlock;
1214
1215 kernel_to_ipc64_perm(&sma->sem_perm, &semid64->sem_perm);
1216 semid64->sem_otime = get_semotime(sma);
1217 semid64->sem_ctime = sma->sem_ctime;
1218 semid64->sem_nsems = sma->sem_nsems;
1219 rcu_read_unlock();
1220 return id;
1221
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222out_unlock:
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001223 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 return err;
1225}
1226
Al Viro45a4a642017-07-09 09:11:00 -04001227static int semctl_info(struct ipc_namespace *ns, int semid,
1228 int cmd, void __user *p)
1229{
1230 struct seminfo seminfo;
1231 int max_id;
1232 int err;
1233
1234 err = security_sem_semctl(NULL, cmd);
1235 if (err)
1236 return err;
1237
1238 memset(&seminfo, 0, sizeof(seminfo));
1239 seminfo.semmni = ns->sc_semmni;
1240 seminfo.semmns = ns->sc_semmns;
1241 seminfo.semmsl = ns->sc_semmsl;
1242 seminfo.semopm = ns->sc_semopm;
1243 seminfo.semvmx = SEMVMX;
1244 seminfo.semmnu = SEMMNU;
1245 seminfo.semmap = SEMMAP;
1246 seminfo.semume = SEMUME;
1247 down_read(&sem_ids(ns).rwsem);
1248 if (cmd == SEM_INFO) {
1249 seminfo.semusz = sem_ids(ns).in_use;
1250 seminfo.semaem = ns->used_sems;
1251 } else {
1252 seminfo.semusz = SEMUSZ;
1253 seminfo.semaem = SEMAEM;
1254 }
1255 max_id = ipc_get_maxid(&sem_ids(ns));
1256 up_read(&sem_ids(ns).rwsem);
1257 if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
1258 return -EFAULT;
1259 return (max_id < 0) ? 0 : max_id;
1260}
1261
Al Viroe1fd1f42013-03-05 15:04:55 -05001262static int semctl_setval(struct ipc_namespace *ns, int semid, int semnum,
Al Viro45a4a642017-07-09 09:11:00 -04001263 int val)
Al Viroe1fd1f42013-03-05 15:04:55 -05001264{
1265 struct sem_undo *un;
1266 struct sem_array *sma;
Manfred Spraul239521f2014-01-27 17:07:04 -08001267 struct sem *curr;
Al Viro45a4a642017-07-09 09:11:00 -04001268 int err;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001269 DEFINE_WAKE_Q(wake_q);
1270
Rik van Riel6062a8d2013-04-30 19:15:44 -07001271 if (val > SEMVMX || val < 0)
1272 return -ERANGE;
Al Viroe1fd1f42013-03-05 15:04:55 -05001273
Rik van Riel6062a8d2013-04-30 19:15:44 -07001274 rcu_read_lock();
1275 sma = sem_obtain_object_check(ns, semid);
1276 if (IS_ERR(sma)) {
1277 rcu_read_unlock();
1278 return PTR_ERR(sma);
1279 }
1280
1281 if (semnum < 0 || semnum >= sma->sem_nsems) {
1282 rcu_read_unlock();
1283 return -EINVAL;
1284 }
1285
1286
1287 if (ipcperms(ns, &sma->sem_perm, S_IWUGO)) {
1288 rcu_read_unlock();
1289 return -EACCES;
1290 }
Al Viroe1fd1f42013-03-05 15:04:55 -05001291
1292 err = security_sem_semctl(sma, SETVAL);
Rik van Riel6062a8d2013-04-30 19:15:44 -07001293 if (err) {
1294 rcu_read_unlock();
1295 return -EACCES;
1296 }
Al Viroe1fd1f42013-03-05 15:04:55 -05001297
Rik van Riel6062a8d2013-04-30 19:15:44 -07001298 sem_lock(sma, NULL, -1);
Al Viroe1fd1f42013-03-05 15:04:55 -05001299
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001300 if (!ipc_valid_object(&sma->sem_perm)) {
Manfred Spraul6e224f92013-10-16 13:46:45 -07001301 sem_unlock(sma, -1);
1302 rcu_read_unlock();
1303 return -EIDRM;
1304 }
1305
Manfred Spraul1a233952017-07-12 14:34:38 -07001306 curr = &sma->sems[semnum];
Al Viroe1fd1f42013-03-05 15:04:55 -05001307
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -07001308 ipc_assert_locked_object(&sma->sem_perm);
Al Viroe1fd1f42013-03-05 15:04:55 -05001309 list_for_each_entry(un, &sma->list_id, list_id)
1310 un->semadj[semnum] = 0;
1311
1312 curr->semval = val;
1313 curr->sempid = task_tgid_vnr(current);
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001314 sma->sem_ctime = ktime_get_real_seconds();
Al Viroe1fd1f42013-03-05 15:04:55 -05001315 /* maybe some queued-up processes were waiting for this */
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001316 do_smart_update(sma, NULL, 0, 0, &wake_q);
Rik van Riel6062a8d2013-04-30 19:15:44 -07001317 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001318 rcu_read_unlock();
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001319 wake_up_q(&wake_q);
Rik van Riel6062a8d2013-04-30 19:15:44 -07001320 return 0;
Al Viroe1fd1f42013-03-05 15:04:55 -05001321}
1322
Kirill Korotaeve3893532006-10-02 02:18:22 -07001323static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
Al Viroe1fd1f42013-03-05 15:04:55 -05001324 int cmd, void __user *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325{
1326 struct sem_array *sma;
Manfred Spraul239521f2014-01-27 17:07:04 -08001327 struct sem *curr;
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001328 int err, nsems;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 ushort fast_sem_io[SEMMSL_FAST];
Manfred Spraul239521f2014-01-27 17:07:04 -08001330 ushort *sem_io = fast_sem_io;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001331 DEFINE_WAKE_Q(wake_q);
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001332
1333 rcu_read_lock();
1334 sma = sem_obtain_object_check(ns, semid);
1335 if (IS_ERR(sma)) {
1336 rcu_read_unlock();
1337 return PTR_ERR(sma);
1338 }
1339
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 nsems = sma->sem_nsems;
1341
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342 err = -EACCES;
Linus Torvaldsc728b9c2013-05-04 11:04:29 -07001343 if (ipcperms(ns, &sma->sem_perm, cmd == SETALL ? S_IWUGO : S_IRUGO))
1344 goto out_rcu_wakeup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
1346 err = security_sem_semctl(sma, cmd);
Linus Torvaldsc728b9c2013-05-04 11:04:29 -07001347 if (err)
1348 goto out_rcu_wakeup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349
1350 err = -EACCES;
1351 switch (cmd) {
1352 case GETALL:
1353 {
Al Viroe1fd1f42013-03-05 15:04:55 -05001354 ushort __user *array = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 int i;
1356
Al Viroce857222013-05-03 00:30:49 +01001357 sem_lock(sma, NULL, -1);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001358 if (!ipc_valid_object(&sma->sem_perm)) {
Manfred Spraul6e224f92013-10-16 13:46:45 -07001359 err = -EIDRM;
1360 goto out_unlock;
1361 }
Manfred Spraul239521f2014-01-27 17:07:04 -08001362 if (nsems > SEMMSL_FAST) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001363 if (!ipc_rcu_getref(&sma->sem_perm)) {
Al Viroce857222013-05-03 00:30:49 +01001364 err = -EIDRM;
Manfred Spraul6e224f92013-10-16 13:46:45 -07001365 goto out_unlock;
Al Viroce857222013-05-03 00:30:49 +01001366 }
1367 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001368 rcu_read_unlock();
Kees Cookf8dbe8d2017-07-12 14:34:47 -07001369 sem_io = kvmalloc_array(nsems, sizeof(ushort),
1370 GFP_KERNEL);
Manfred Spraul239521f2014-01-27 17:07:04 -08001371 if (sem_io == NULL) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001372 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373 return -ENOMEM;
1374 }
1375
Linus Torvalds4091fd92013-05-04 10:13:40 -07001376 rcu_read_lock();
Pierre Peiffer6ff37972008-04-29 01:00:46 -07001377 sem_lock_and_putref(sma);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001378 if (!ipc_valid_object(&sma->sem_perm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 err = -EIDRM;
Manfred Spraul6e224f92013-10-16 13:46:45 -07001380 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 }
Al Viroce857222013-05-03 00:30:49 +01001382 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 for (i = 0; i < sma->sem_nsems; i++)
Manfred Spraul1a233952017-07-12 14:34:38 -07001384 sem_io[i] = sma->sems[i].semval;
Rik van Riel6062a8d2013-04-30 19:15:44 -07001385 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001386 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 err = 0;
Manfred Spraul239521f2014-01-27 17:07:04 -08001388 if (copy_to_user(array, sem_io, nsems*sizeof(ushort)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389 err = -EFAULT;
1390 goto out_free;
1391 }
1392 case SETALL:
1393 {
1394 int i;
1395 struct sem_undo *un;
1396
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001397 if (!ipc_rcu_getref(&sma->sem_perm)) {
Manfred Spraul6e224f92013-10-16 13:46:45 -07001398 err = -EIDRM;
1399 goto out_rcu_wakeup;
Rik van Riel6062a8d2013-04-30 19:15:44 -07001400 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001401 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402
Manfred Spraul239521f2014-01-27 17:07:04 -08001403 if (nsems > SEMMSL_FAST) {
Kees Cookf8dbe8d2017-07-12 14:34:47 -07001404 sem_io = kvmalloc_array(nsems, sizeof(ushort),
1405 GFP_KERNEL);
Manfred Spraul239521f2014-01-27 17:07:04 -08001406 if (sem_io == NULL) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001407 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 return -ENOMEM;
1409 }
1410 }
1411
Manfred Spraul239521f2014-01-27 17:07:04 -08001412 if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001413 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414 err = -EFAULT;
1415 goto out_free;
1416 }
1417
1418 for (i = 0; i < nsems; i++) {
1419 if (sem_io[i] > SEMVMX) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001420 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421 err = -ERANGE;
1422 goto out_free;
1423 }
1424 }
Linus Torvalds4091fd92013-05-04 10:13:40 -07001425 rcu_read_lock();
Pierre Peiffer6ff37972008-04-29 01:00:46 -07001426 sem_lock_and_putref(sma);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001427 if (!ipc_valid_object(&sma->sem_perm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428 err = -EIDRM;
Manfred Spraul6e224f92013-10-16 13:46:45 -07001429 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 }
1431
Davidlohr Buesoa5f4db82016-03-22 14:27:48 -07001432 for (i = 0; i < nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -07001433 sma->sems[i].semval = sem_io[i];
1434 sma->sems[i].sempid = task_tgid_vnr(current);
Davidlohr Buesoa5f4db82016-03-22 14:27:48 -07001435 }
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001436
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -07001437 ipc_assert_locked_object(&sma->sem_perm);
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001438 list_for_each_entry(un, &sma->list_id, list_id) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 for (i = 0; i < nsems; i++)
1440 un->semadj[i] = 0;
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001441 }
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001442 sma->sem_ctime = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 /* maybe some queued-up processes were waiting for this */
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001444 do_smart_update(sma, NULL, 0, 0, &wake_q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445 err = 0;
1446 goto out_unlock;
1447 }
Al Viroe1fd1f42013-03-05 15:04:55 -05001448 /* GETVAL, GETPID, GETNCTN, GETZCNT: fall-through */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 }
1450 err = -EINVAL;
Linus Torvaldsc728b9c2013-05-04 11:04:29 -07001451 if (semnum < 0 || semnum >= nsems)
1452 goto out_rcu_wakeup;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453
Rik van Riel6062a8d2013-04-30 19:15:44 -07001454 sem_lock(sma, NULL, -1);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001455 if (!ipc_valid_object(&sma->sem_perm)) {
Manfred Spraul6e224f92013-10-16 13:46:45 -07001456 err = -EIDRM;
1457 goto out_unlock;
1458 }
Manfred Spraul1a233952017-07-12 14:34:38 -07001459 curr = &sma->sems[semnum];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
1461 switch (cmd) {
1462 case GETVAL:
1463 err = curr->semval;
1464 goto out_unlock;
1465 case GETPID:
1466 err = curr->sempid;
1467 goto out_unlock;
1468 case GETNCNT:
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001469 err = count_semcnt(sma, semnum, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470 goto out_unlock;
1471 case GETZCNT:
Manfred Spraul2f2ed41d2014-06-06 14:37:48 -07001472 err = count_semcnt(sma, semnum, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001475
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476out_unlock:
Rik van Riel6062a8d2013-04-30 19:15:44 -07001477 sem_unlock(sma, -1);
Linus Torvaldsc728b9c2013-05-04 11:04:29 -07001478out_rcu_wakeup:
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001479 rcu_read_unlock();
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001480 wake_up_q(&wake_q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481out_free:
Manfred Spraul239521f2014-01-27 17:07:04 -08001482 if (sem_io != fast_sem_io)
Kees Cookf8dbe8d2017-07-12 14:34:47 -07001483 kvfree(sem_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 return err;
1485}
1486
Pierre Peiffer016d7132008-04-29 01:00:50 -07001487static inline unsigned long
1488copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489{
Manfred Spraul239521f2014-01-27 17:07:04 -08001490 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -07001492 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 case IPC_OLD:
1496 {
1497 struct semid_ds tbuf_old;
1498
Manfred Spraul239521f2014-01-27 17:07:04 -08001499 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 return -EFAULT;
1501
Pierre Peiffer016d7132008-04-29 01:00:50 -07001502 out->sem_perm.uid = tbuf_old.sem_perm.uid;
1503 out->sem_perm.gid = tbuf_old.sem_perm.gid;
1504 out->sem_perm.mode = tbuf_old.sem_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001505
1506 return 0;
1507 }
1508 default:
1509 return -EINVAL;
1510 }
1511}
1512
Pierre Peiffer522bb2a2008-04-29 01:00:49 -07001513/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001514 * This function handles some semctl commands which require the rwsem
Pierre Peiffer522bb2a2008-04-29 01:00:49 -07001515 * to be held in write mode.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001516 * NOTE: no locks must be held, the rwsem is taken inside this function.
Pierre Peiffer522bb2a2008-04-29 01:00:49 -07001517 */
Pierre Peiffer21a48262008-04-29 01:00:49 -07001518static int semctl_down(struct ipc_namespace *ns, int semid,
Al Viro45a4a642017-07-09 09:11:00 -04001519 int cmd, struct semid64_ds *semid64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001520{
1521 struct sem_array *sma;
1522 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 struct kern_ipc_perm *ipcp;
1524
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001525 down_write(&sem_ids(ns).rwsem);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001526 rcu_read_lock();
1527
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001528 ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
Al Viro45a4a642017-07-09 09:11:00 -04001529 &semid64->sem_perm, 0);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001530 if (IS_ERR(ipcp)) {
1531 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001532 goto out_unlock1;
1533 }
Steve Grubb073115d2006-04-02 17:07:33 -04001534
Pierre Peiffera5f75e72008-04-29 01:00:54 -07001535 sma = container_of(ipcp, struct sem_array, sem_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536
1537 err = security_sem_semctl(sma, cmd);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001538 if (err)
1539 goto out_unlock1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001541 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542 case IPC_RMID:
Rik van Riel6062a8d2013-04-30 19:15:44 -07001543 sem_lock(sma, NULL, -1);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001544 /* freeary unlocks the ipc object and rcu */
Pierre Peiffer01b8b072008-02-08 04:18:57 -08001545 freeary(ns, ipcp);
Pierre Peiffer522bb2a2008-04-29 01:00:49 -07001546 goto out_up;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547 case IPC_SET:
Rik van Riel6062a8d2013-04-30 19:15:44 -07001548 sem_lock(sma, NULL, -1);
Al Viro45a4a642017-07-09 09:11:00 -04001549 err = ipc_update_perm(&semid64->sem_perm, ipcp);
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001550 if (err)
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001551 goto out_unlock0;
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07001552 sma->sem_ctime = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553 break;
1554 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555 err = -EINVAL;
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001556 goto out_unlock1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001559out_unlock0:
Rik van Riel6062a8d2013-04-30 19:15:44 -07001560 sem_unlock(sma, -1);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001561out_unlock1:
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001562 rcu_read_unlock();
Pierre Peiffer522bb2a2008-04-29 01:00:49 -07001563out_up:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001564 up_write(&sem_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001565 return err;
1566}
1567
Al Viroe1fd1f42013-03-05 15:04:55 -05001568SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, unsigned long, arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570 int version;
Kirill Korotaeve3893532006-10-02 02:18:22 -07001571 struct ipc_namespace *ns;
Al Viroe1fd1f42013-03-05 15:04:55 -05001572 void __user *p = (void __user *)arg;
Al Viro45a4a642017-07-09 09:11:00 -04001573 struct semid64_ds semid64;
1574 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575
1576 if (semid < 0)
1577 return -EINVAL;
1578
1579 version = ipc_parse_version(&cmd);
Kirill Korotaeve3893532006-10-02 02:18:22 -07001580 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001581
Manfred Spraul239521f2014-01-27 17:07:04 -08001582 switch (cmd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 case IPC_INFO:
1584 case SEM_INFO:
Al Viro45a4a642017-07-09 09:11:00 -04001585 return semctl_info(ns, semid, cmd, p);
Pierre Peiffer4b9fcb02008-02-08 04:18:56 -08001586 case IPC_STAT:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587 case SEM_STAT:
Al Viro45a4a642017-07-09 09:11:00 -04001588 err = semctl_stat(ns, semid, cmd, &semid64);
1589 if (err < 0)
1590 return err;
1591 if (copy_semid_to_user(p, &semid64, version))
1592 err = -EFAULT;
1593 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594 case GETALL:
1595 case GETVAL:
1596 case GETPID:
1597 case GETNCNT:
1598 case GETZCNT:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 case SETALL:
Al Viroe1fd1f42013-03-05 15:04:55 -05001600 return semctl_main(ns, semid, semnum, cmd, p);
Al Viro45a4a642017-07-09 09:11:00 -04001601 case SETVAL: {
1602 int val;
1603#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
1604 /* big-endian 64bit */
1605 val = arg >> 32;
1606#else
1607 /* 32bit or little-endian 64bit */
1608 val = arg;
1609#endif
1610 return semctl_setval(ns, semid, semnum, val);
1611 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 case IPC_SET:
Al Viro45a4a642017-07-09 09:11:00 -04001613 if (copy_semid_from_user(&semid64, p, version))
1614 return -EFAULT;
1615 case IPC_RMID:
1616 return semctl_down(ns, semid, cmd, &semid64);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617 default:
1618 return -EINVAL;
1619 }
1620}
1621
Al Viroc0ebccb2017-07-09 10:03:23 -04001622#ifdef CONFIG_COMPAT
1623
1624struct compat_semid_ds {
1625 struct compat_ipc_perm sem_perm;
1626 compat_time_t sem_otime;
1627 compat_time_t sem_ctime;
1628 compat_uptr_t sem_base;
1629 compat_uptr_t sem_pending;
1630 compat_uptr_t sem_pending_last;
1631 compat_uptr_t undo;
1632 unsigned short sem_nsems;
1633};
1634
1635static int copy_compat_semid_from_user(struct semid64_ds *out, void __user *buf,
1636 int version)
1637{
1638 memset(out, 0, sizeof(*out));
1639 if (version == IPC_64) {
1640 struct compat_semid64_ds *p = buf;
1641 return get_compat_ipc64_perm(&out->sem_perm, &p->sem_perm);
1642 } else {
1643 struct compat_semid_ds *p = buf;
1644 return get_compat_ipc_perm(&out->sem_perm, &p->sem_perm);
1645 }
1646}
1647
1648static int copy_compat_semid_to_user(void __user *buf, struct semid64_ds *in,
1649 int version)
1650{
1651 if (version == IPC_64) {
1652 struct compat_semid64_ds v;
1653 memset(&v, 0, sizeof(v));
1654 to_compat_ipc64_perm(&v.sem_perm, &in->sem_perm);
1655 v.sem_otime = in->sem_otime;
1656 v.sem_ctime = in->sem_ctime;
1657 v.sem_nsems = in->sem_nsems;
1658 return copy_to_user(buf, &v, sizeof(v));
1659 } else {
1660 struct compat_semid_ds v;
1661 memset(&v, 0, sizeof(v));
1662 to_compat_ipc_perm(&v.sem_perm, &in->sem_perm);
1663 v.sem_otime = in->sem_otime;
1664 v.sem_ctime = in->sem_ctime;
1665 v.sem_nsems = in->sem_nsems;
1666 return copy_to_user(buf, &v, sizeof(v));
1667 }
1668}
1669
1670COMPAT_SYSCALL_DEFINE4(semctl, int, semid, int, semnum, int, cmd, int, arg)
1671{
1672 void __user *p = compat_ptr(arg);
1673 struct ipc_namespace *ns;
1674 struct semid64_ds semid64;
1675 int version = compat_ipc_parse_version(&cmd);
1676 int err;
1677
1678 ns = current->nsproxy->ipc_ns;
1679
1680 if (semid < 0)
1681 return -EINVAL;
1682
1683 switch (cmd & (~IPC_64)) {
1684 case IPC_INFO:
1685 case SEM_INFO:
1686 return semctl_info(ns, semid, cmd, p);
1687 case IPC_STAT:
1688 case SEM_STAT:
1689 err = semctl_stat(ns, semid, cmd, &semid64);
1690 if (err < 0)
1691 return err;
1692 if (copy_compat_semid_to_user(p, &semid64, version))
1693 err = -EFAULT;
1694 return err;
1695 case GETVAL:
1696 case GETPID:
1697 case GETNCNT:
1698 case GETZCNT:
1699 case GETALL:
1700 case SETALL:
1701 return semctl_main(ns, semid, semnum, cmd, p);
1702 case SETVAL:
1703 return semctl_setval(ns, semid, semnum, arg);
1704 case IPC_SET:
1705 if (copy_compat_semid_from_user(&semid64, p, version))
1706 return -EFAULT;
1707 /* fallthru */
1708 case IPC_RMID:
1709 return semctl_down(ns, semid, cmd, &semid64);
1710 default:
1711 return -EINVAL;
1712 }
1713}
1714#endif
1715
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716/* If the task doesn't already have a undo_list, then allocate one
1717 * here. We guarantee there is only one thread using this undo list,
1718 * and current is THE ONE
1719 *
1720 * If this allocation and assignment succeeds, but later
1721 * portions of this code fail, there is no need to free the sem_undo_list.
1722 * Just let it stay associated with the task, and it'll be freed later
1723 * at exit time.
1724 *
1725 * This can block, so callers must hold no locks.
1726 */
1727static inline int get_undo_list(struct sem_undo_list **undo_listp)
1728{
1729 struct sem_undo_list *undo_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
1731 undo_list = current->sysvsem.undo_list;
1732 if (!undo_list) {
Matt Helsley2453a302006-10-02 02:18:25 -07001733 undo_list = kzalloc(sizeof(*undo_list), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734 if (undo_list == NULL)
1735 return -ENOMEM;
Ingo Molnar00a5dfd2005-08-05 23:05:27 +02001736 spin_lock_init(&undo_list->lock);
Elena Reshetovaf74370b2017-09-08 16:17:42 -07001737 refcount_set(&undo_list->refcnt, 1);
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001738 INIT_LIST_HEAD(&undo_list->list_proc);
1739
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 current->sysvsem.undo_list = undo_list;
1741 }
1742 *undo_listp = undo_list;
1743 return 0;
1744}
1745
Nick Pigginbf17bb72009-12-15 16:47:28 -08001746static struct sem_undo *__lookup_undo(struct sem_undo_list *ulp, int semid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747{
Nick Pigginbf17bb72009-12-15 16:47:28 -08001748 struct sem_undo *un;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749
Nick Pigginbf17bb72009-12-15 16:47:28 -08001750 list_for_each_entry_rcu(un, &ulp->list_proc, list_proc) {
1751 if (un->semid == semid)
1752 return un;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 }
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001754 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755}
1756
Nick Pigginbf17bb72009-12-15 16:47:28 -08001757static struct sem_undo *lookup_undo(struct sem_undo_list *ulp, int semid)
1758{
1759 struct sem_undo *un;
1760
Manfred Spraul239521f2014-01-27 17:07:04 -08001761 assert_spin_locked(&ulp->lock);
Nick Pigginbf17bb72009-12-15 16:47:28 -08001762
1763 un = __lookup_undo(ulp, semid);
1764 if (un) {
1765 list_del_rcu(&un->list_proc);
1766 list_add_rcu(&un->list_proc, &ulp->list_proc);
1767 }
1768 return un;
1769}
1770
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001771/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -08001772 * find_alloc_undo - lookup (and if not present create) undo array
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001773 * @ns: namespace
1774 * @semid: semaphore array id
1775 *
1776 * The function looks up (and if not present creates) the undo structure.
1777 * The size of the undo structure depends on the size of the semaphore
1778 * array, thus the alloc path is not that straightforward.
Manfred Spraul380af1b2008-07-25 01:48:06 -07001779 * Lifetime-rules: sem_undo is rcu-protected, on success, the function
1780 * performs a rcu_read_lock().
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001781 */
1782static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783{
1784 struct sem_array *sma;
1785 struct sem_undo_list *ulp;
1786 struct sem_undo *un, *new;
Rik van Riel6062a8d2013-04-30 19:15:44 -07001787 int nsems, error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788
1789 error = get_undo_list(&ulp);
1790 if (error)
1791 return ERR_PTR(error);
1792
Manfred Spraul380af1b2008-07-25 01:48:06 -07001793 rcu_read_lock();
Pierre Peifferc530c6a2007-10-18 23:40:55 -07001794 spin_lock(&ulp->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 un = lookup_undo(ulp, semid);
Pierre Peifferc530c6a2007-10-18 23:40:55 -07001796 spin_unlock(&ulp->lock);
Manfred Spraul239521f2014-01-27 17:07:04 -08001797 if (likely(un != NULL))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 goto out;
1799
1800 /* no undo structure around - allocate one. */
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001801 /* step 1: figure out the size of the semaphore array */
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001802 sma = sem_obtain_object_check(ns, semid);
1803 if (IS_ERR(sma)) {
1804 rcu_read_unlock();
Julia Lawall4de85cd2010-05-26 14:43:44 -07001805 return ERR_CAST(sma);
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001806 }
Nadia Derbey023a5352007-10-18 23:40:51 -07001807
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 nsems = sma->sem_nsems;
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001809 if (!ipc_rcu_getref(&sma->sem_perm)) {
Rik van Riel6062a8d2013-04-30 19:15:44 -07001810 rcu_read_unlock();
1811 un = ERR_PTR(-EIDRM);
1812 goto out;
1813 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001814 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001816 /* step 2: allocate new undo structure */
Burman Yan4668edc2006-12-06 20:38:51 -08001817 new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001818 if (!new) {
Manfred Sprauldba4cdd2017-07-12 14:34:41 -07001819 ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 return ERR_PTR(-ENOMEM);
1821 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822
Manfred Spraul380af1b2008-07-25 01:48:06 -07001823 /* step 3: Acquire the lock on semaphore array */
Linus Torvalds4091fd92013-05-04 10:13:40 -07001824 rcu_read_lock();
Pierre Peiffer6ff37972008-04-29 01:00:46 -07001825 sem_lock_and_putref(sma);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001826 if (!ipc_valid_object(&sma->sem_perm)) {
Rik van Riel6062a8d2013-04-30 19:15:44 -07001827 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07001828 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 kfree(new);
1830 un = ERR_PTR(-EIDRM);
1831 goto out;
1832 }
Manfred Spraul380af1b2008-07-25 01:48:06 -07001833 spin_lock(&ulp->lock);
1834
1835 /*
1836 * step 4: check for races: did someone else allocate the undo struct?
1837 */
1838 un = lookup_undo(ulp, semid);
1839 if (un) {
1840 kfree(new);
1841 goto success;
1842 }
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001843 /* step 5: initialize & link new undo structure */
1844 new->semadj = (short *) &new[1];
Manfred Spraul380af1b2008-07-25 01:48:06 -07001845 new->ulp = ulp;
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001846 new->semid = semid;
1847 assert_spin_locked(&ulp->lock);
Manfred Spraul380af1b2008-07-25 01:48:06 -07001848 list_add_rcu(&new->list_proc, &ulp->list_proc);
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -07001849 ipc_assert_locked_object(&sma->sem_perm);
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001850 list_add(&new->list_id, &sma->list_id);
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001851 un = new;
Manfred Spraul380af1b2008-07-25 01:48:06 -07001852
1853success:
1854 spin_unlock(&ulp->lock);
Rik van Riel6062a8d2013-04-30 19:15:44 -07001855 sem_unlock(sma, -1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856out:
1857 return un;
1858}
1859
Al Viro44ee4542017-07-09 10:50:14 -04001860static long do_semtimedop(int semid, struct sembuf __user *tsops,
Deepa Dinamani3ef56dc2017-08-02 19:51:10 -07001861 unsigned nsops, const struct timespec64 *timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862{
1863 int error = -EINVAL;
1864 struct sem_array *sma;
1865 struct sembuf fast_sops[SEMOPM_FAST];
Manfred Spraul239521f2014-01-27 17:07:04 -08001866 struct sembuf *sops = fast_sops, *sop;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 struct sem_undo *un;
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001868 int max, locknum;
1869 bool undos = false, alter = false, dupsop = false;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001870 struct sem_queue queue;
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001871 unsigned long dup = 0, jiffies_left = 0;
Kirill Korotaeve3893532006-10-02 02:18:22 -07001872 struct ipc_namespace *ns;
1873
1874 ns = current->nsproxy->ipc_ns;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875
1876 if (nsops < 1 || semid < 0)
1877 return -EINVAL;
Kirill Korotaeve3893532006-10-02 02:18:22 -07001878 if (nsops > ns->sc_semopm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001879 return -E2BIG;
Manfred Spraul239521f2014-01-27 17:07:04 -08001880 if (nsops > SEMOPM_FAST) {
Davidlohr Buesoe4243b82017-09-08 16:17:52 -07001881 sops = kvmalloc(sizeof(*sops)*nsops, GFP_KERNEL);
Manfred Spraul239521f2014-01-27 17:07:04 -08001882 if (sops == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883 return -ENOMEM;
1884 }
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001885
Manfred Spraul239521f2014-01-27 17:07:04 -08001886 if (copy_from_user(sops, tsops, nsops * sizeof(*tsops))) {
1887 error = -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 goto out_free;
1889 }
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001890
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 if (timeout) {
Al Viro44ee4542017-07-09 10:50:14 -04001892 if (timeout->tv_sec < 0 || timeout->tv_nsec < 0 ||
1893 timeout->tv_nsec >= 1000000000L) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 error = -EINVAL;
1895 goto out_free;
1896 }
Deepa Dinamani3ef56dc2017-08-02 19:51:10 -07001897 jiffies_left = timespec64_to_jiffies(timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 }
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001899
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900 max = 0;
1901 for (sop = sops; sop < sops + nsops; sop++) {
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001902 unsigned long mask = 1ULL << ((sop->sem_num) % BITS_PER_LONG);
1903
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904 if (sop->sem_num >= max)
1905 max = sop->sem_num;
1906 if (sop->sem_flg & SEM_UNDO)
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001907 undos = true;
1908 if (dup & mask) {
1909 /*
1910 * There was a previous alter access that appears
1911 * to have accessed the same semaphore, thus use
1912 * the dupsop logic. "appears", because the detection
1913 * can only check % BITS_PER_LONG.
1914 */
1915 dupsop = true;
1916 }
1917 if (sop->sem_op != 0) {
1918 alter = true;
1919 dup |= mask;
1920 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923 if (undos) {
Rik van Riel6062a8d2013-04-30 19:15:44 -07001924 /* On success, find_alloc_undo takes the rcu_read_lock */
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001925 un = find_alloc_undo(ns, semid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 if (IS_ERR(un)) {
1927 error = PTR_ERR(un);
1928 goto out_free;
1929 }
Rik van Riel6062a8d2013-04-30 19:15:44 -07001930 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001931 un = NULL;
Rik van Riel6062a8d2013-04-30 19:15:44 -07001932 rcu_read_lock();
1933 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001935 sma = sem_obtain_object_check(ns, semid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001936 if (IS_ERR(sma)) {
Rik van Riel6062a8d2013-04-30 19:15:44 -07001937 rcu_read_unlock();
Nadia Derbey023a5352007-10-18 23:40:51 -07001938 error = PTR_ERR(sma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 goto out_free;
Nadia Derbey023a5352007-10-18 23:40:51 -07001940 }
1941
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001942 error = -EFBIG;
Davidlohr Bueso248e7352016-12-14 15:06:31 -08001943 if (max >= sma->sem_nsems) {
1944 rcu_read_unlock();
1945 goto out_free;
1946 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001947
1948 error = -EACCES;
Davidlohr Bueso248e7352016-12-14 15:06:31 -08001949 if (ipcperms(ns, &sma->sem_perm, alter ? S_IWUGO : S_IRUGO)) {
1950 rcu_read_unlock();
1951 goto out_free;
1952 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001953
1954 error = security_sem_semop(sma, sops, nsops, alter);
Davidlohr Bueso248e7352016-12-14 15:06:31 -08001955 if (error) {
1956 rcu_read_unlock();
1957 goto out_free;
1958 }
Davidlohr Bueso16df3672013-04-30 19:15:29 -07001959
Manfred Spraul6e224f92013-10-16 13:46:45 -07001960 error = -EIDRM;
1961 locknum = sem_lock(sma, sops, nsops);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001962 /*
1963 * We eventually might perform the following check in a lockless
1964 * fashion, considering ipc_valid_object() locking constraints.
1965 * If nsops == 1 and there is no contention for sem_perm.lock, then
1966 * only a per-semaphore lock is held and it's OK to proceed with the
1967 * check below. More details on the fine grained locking scheme
1968 * entangled here and why it's RMID race safe on comments at sem_lock()
1969 */
1970 if (!ipc_valid_object(&sma->sem_perm))
Manfred Spraul6e224f92013-10-16 13:46:45 -07001971 goto out_unlock_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 /*
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001973 * semid identifiers are not unique - find_alloc_undo may have
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 * allocated an undo structure, it was invalidated by an RMID
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001975 * and now a new array with received the same id. Check and fail.
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001976 * This case can be detected checking un->semid. The existence of
Manfred Spraul380af1b2008-07-25 01:48:06 -07001977 * "un" itself is guaranteed by rcu.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 */
Rik van Riel6062a8d2013-04-30 19:15:44 -07001979 if (un && un->semid == -1)
1980 goto out_unlock_free;
Manfred Spraul4daa28f2008-07-25 01:48:04 -07001981
Manfred Sprauld198cd62014-06-06 14:37:49 -07001982 queue.sops = sops;
1983 queue.nsops = nsops;
1984 queue.undo = un;
1985 queue.pid = task_tgid_vnr(current);
1986 queue.alter = alter;
Davidlohr Bueso4ce33ec2016-12-14 15:06:37 -08001987 queue.dupsop = dupsop;
Manfred Sprauld198cd62014-06-06 14:37:49 -07001988
1989 error = perform_atomic_semop(sma, &queue);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001990 if (error == 0) { /* non-blocking succesfull path */
1991 DEFINE_WAKE_Q(wake_q);
1992
1993 /*
1994 * If the operation was successful, then do
Manfred Spraul0e8c6652013-09-30 13:45:25 -07001995 * the required updates.
1996 */
1997 if (alter)
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08001998 do_smart_update(sma, sops, nsops, 1, &wake_q);
Manfred Spraul0e8c6652013-09-30 13:45:25 -07001999 else
2000 set_semotime(sma, sops);
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002001
2002 sem_unlock(sma, locknum);
2003 rcu_read_unlock();
2004 wake_up_q(&wake_q);
2005
2006 goto out_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007 }
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002008 if (error < 0) /* non-blocking error path */
Manfred Spraul0e8c6652013-09-30 13:45:25 -07002009 goto out_unlock_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002011 /*
2012 * We need to sleep on this operation, so we put the current
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 * task into the pending queue and go to sleep.
2014 */
Manfred Spraulb97e8202009-12-15 16:47:32 -08002015 if (nsops == 1) {
2016 struct sem *curr;
Manfred Spraul1a233952017-07-12 14:34:38 -07002017 curr = &sma->sems[sops->sem_num];
Manfred Spraulb97e8202009-12-15 16:47:32 -08002018
Manfred Spraulf269f402013-07-08 16:01:24 -07002019 if (alter) {
2020 if (sma->complex_count) {
2021 list_add_tail(&queue.list,
2022 &sma->pending_alter);
2023 } else {
2024
2025 list_add_tail(&queue.list,
2026 &curr->pending_alter);
2027 }
2028 } else {
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07002029 list_add_tail(&queue.list, &curr->pending_const);
Manfred Spraulf269f402013-07-08 16:01:24 -07002030 }
Manfred Spraulb97e8202009-12-15 16:47:32 -08002031 } else {
Manfred Spraulf269f402013-07-08 16:01:24 -07002032 if (!sma->complex_count)
2033 merge_queues(sma);
2034
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07002035 if (alter)
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07002036 list_add_tail(&queue.list, &sma->pending_alter);
Rik van Riel9f1bc2c92013-04-30 19:15:39 -07002037 else
Manfred Spraul1a82e9e2013-07-08 16:01:23 -07002038 list_add_tail(&queue.list, &sma->pending_const);
2039
Manfred Spraulb97e8202009-12-15 16:47:32 -08002040 sma->complex_count++;
2041 }
2042
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002043 do {
Davidlohr Bueso92c15982018-07-26 16:37:19 -07002044 WRITE_ONCE(queue.status, -EINTR);
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002045 queue.sleeper = current;
Manfred Spraul0b0577f2011-11-02 13:38:52 -07002046
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002047 __set_current_state(TASK_INTERRUPTIBLE);
2048 sem_unlock(sma, locknum);
Linus Torvalds321310c2013-05-04 10:47:57 -07002049 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002050
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002051 if (timeout)
2052 jiffies_left = schedule_timeout(jiffies_left);
2053 else
2054 schedule();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002056 /*
2057 * fastpath: the semop has completed, either successfully or
2058 * not, from the syscall pov, is quite irrelevant to us at this
2059 * point; we're done.
2060 *
2061 * We _do_ care, nonetheless, about being awoken by a signal or
2062 * spuriously. The queue.status is checked again in the
2063 * slowpath (aka after taking sem_lock), such that we can detect
2064 * scenarios where we were awakened externally, during the
2065 * window between wake_q_add() and wake_up_q().
2066 */
2067 error = READ_ONCE(queue.status);
2068 if (error != -EINTR) {
2069 /*
2070 * User space could assume that semop() is a memory
2071 * barrier: Without the mb(), the cpu could
2072 * speculatively read in userspace stale data that was
2073 * overwritten by the previous owner of the semaphore.
2074 */
2075 smp_mb();
2076 goto out_free;
2077 }
Manfred Spraul0b0577f2011-11-02 13:38:52 -07002078
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002079 rcu_read_lock();
Manfred Spraulc626bc42017-01-10 16:57:48 -08002080 locknum = sem_lock(sma, sops, nsops);
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002081
Davidlohr Bueso370b2622016-12-14 15:06:49 -08002082 if (!ipc_valid_object(&sma->sem_perm))
2083 goto out_unlock_free;
2084
2085 error = READ_ONCE(queue.status);
Davidlohr Buesob5fa01a2016-12-14 15:06:46 -08002086
2087 /*
2088 * If queue.status != -EINTR we are woken up by another process.
2089 * Leave without unlink_queue(), but with sem_unlock().
2090 */
2091 if (error != -EINTR)
2092 goto out_unlock_free;
2093
2094 /*
2095 * If an interrupt occurred we have to clean up the queue.
2096 */
2097 if (timeout && jiffies_left == 0)
2098 error = -EAGAIN;
2099 } while (error == -EINTR && !signal_pending(current)); /* spurious */
Manfred Spraul0b0577f2011-11-02 13:38:52 -07002100
Manfred Spraulb97e8202009-12-15 16:47:32 -08002101 unlink_queue(sma, &queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102
2103out_unlock_free:
Rik van Riel6062a8d2013-04-30 19:15:44 -07002104 sem_unlock(sma, locknum);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07002105 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002106out_free:
Manfred Spraul239521f2014-01-27 17:07:04 -08002107 if (sops != fast_sops)
Davidlohr Buesoe4243b82017-09-08 16:17:52 -07002108 kvfree(sops);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109 return error;
2110}
2111
Al Viro44ee4542017-07-09 10:50:14 -04002112SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
2113 unsigned, nsops, const struct timespec __user *, timeout)
2114{
2115 if (timeout) {
Deepa Dinamani3ef56dc2017-08-02 19:51:10 -07002116 struct timespec64 ts;
2117 if (get_timespec64(&ts, timeout))
Al Viro44ee4542017-07-09 10:50:14 -04002118 return -EFAULT;
2119 return do_semtimedop(semid, tsops, nsops, &ts);
2120 }
2121 return do_semtimedop(semid, tsops, nsops, NULL);
2122}
2123
2124#ifdef CONFIG_COMPAT
2125COMPAT_SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsems,
2126 unsigned, nsops,
2127 const struct compat_timespec __user *, timeout)
2128{
2129 if (timeout) {
Deepa Dinamani3ef56dc2017-08-02 19:51:10 -07002130 struct timespec64 ts;
2131 if (compat_get_timespec64(&ts, timeout))
Al Viro44ee4542017-07-09 10:50:14 -04002132 return -EFAULT;
2133 return do_semtimedop(semid, tsems, nsops, &ts);
2134 }
2135 return do_semtimedop(semid, tsems, nsops, NULL);
2136}
2137#endif
2138
Heiko Carstensd5460c92009-01-14 14:14:27 +01002139SYSCALL_DEFINE3(semop, int, semid, struct sembuf __user *, tsops,
2140 unsigned, nsops)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002141{
Al Viro44ee4542017-07-09 10:50:14 -04002142 return do_semtimedop(semid, tsops, nsops, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002143}
2144
2145/* If CLONE_SYSVSEM is set, establish sharing of SEM_UNDO state between
2146 * parent and child tasks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002147 */
2148
2149int copy_semundo(unsigned long clone_flags, struct task_struct *tsk)
2150{
2151 struct sem_undo_list *undo_list;
2152 int error;
2153
2154 if (clone_flags & CLONE_SYSVSEM) {
2155 error = get_undo_list(&undo_list);
2156 if (error)
2157 return error;
Elena Reshetovaf74370b2017-09-08 16:17:42 -07002158 refcount_inc(&undo_list->refcnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 tsk->sysvsem.undo_list = undo_list;
Paul McQuade46c0a8c2014-06-06 14:37:37 -07002160 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161 tsk->sysvsem.undo_list = NULL;
2162
2163 return 0;
2164}
2165
2166/*
2167 * add semadj values to semaphores, free undo structures.
2168 * undo structures are not freed when semaphore arrays are destroyed
2169 * so some of them may be out of date.
2170 * IMPLEMENTATION NOTE: There is some confusion over whether the
2171 * set of adjustments that needs to be done should be done in an atomic
2172 * manner or not. That is, if we are attempting to decrement the semval
2173 * should we queue up and wait until we can do so legally?
2174 * The original implementation attempted to do this (queue and wait).
2175 * The current implementation does not do so. The POSIX standard
2176 * and SVID should be consulted to determine what behavior is mandated.
2177 */
2178void exit_sem(struct task_struct *tsk)
2179{
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002180 struct sem_undo_list *ulp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002181
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002182 ulp = tsk->sysvsem.undo_list;
2183 if (!ulp)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184 return;
Manfred Spraul9edff4a2008-04-29 01:00:57 -07002185 tsk->sysvsem.undo_list = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002186
Elena Reshetovaf74370b2017-09-08 16:17:42 -07002187 if (!refcount_dec_and_test(&ulp->refcnt))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002188 return;
2189
Manfred Spraul380af1b2008-07-25 01:48:06 -07002190 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002191 struct sem_array *sma;
Manfred Spraul380af1b2008-07-25 01:48:06 -07002192 struct sem_undo *un;
Rik van Riel6062a8d2013-04-30 19:15:44 -07002193 int semid, i;
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002194 DEFINE_WAKE_Q(wake_q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195
Nikolay Borisov2a1613a2016-10-11 13:55:05 -07002196 cond_resched();
2197
Manfred Spraul380af1b2008-07-25 01:48:06 -07002198 rcu_read_lock();
Jiri Pirko05725f72009-04-14 20:17:16 +02002199 un = list_entry_rcu(ulp->list_proc.next,
2200 struct sem_undo, list_proc);
Herton R. Krzesinski602b8592015-08-14 15:35:02 -07002201 if (&un->list_proc == &ulp->list_proc) {
2202 /*
2203 * We must wait for freeary() before freeing this ulp,
2204 * in case we raced with last sem_undo. There is a small
2205 * possibility where we exit while freeary() didn't
2206 * finish unlocking sem_undo_list.
2207 */
Paul E. McKenneye0892e02017-06-29 12:59:32 -07002208 spin_lock(&ulp->lock);
2209 spin_unlock(&ulp->lock);
Rik van Riel6062a8d2013-04-30 19:15:44 -07002210 rcu_read_unlock();
Manfred Spraul380af1b2008-07-25 01:48:06 -07002211 break;
Rik van Riel6062a8d2013-04-30 19:15:44 -07002212 }
Herton R. Krzesinski602b8592015-08-14 15:35:02 -07002213 spin_lock(&ulp->lock);
2214 semid = un->semid;
2215 spin_unlock(&ulp->lock);
Manfred Spraul380af1b2008-07-25 01:48:06 -07002216
Herton R. Krzesinski602b8592015-08-14 15:35:02 -07002217 /* exit_sem raced with IPC_RMID, nothing to do */
2218 if (semid == -1) {
2219 rcu_read_unlock();
2220 continue;
2221 }
2222
2223 sma = sem_obtain_object_check(tsk->nsproxy->ipc_ns, semid);
Manfred Spraul380af1b2008-07-25 01:48:06 -07002224 /* exit_sem raced with IPC_RMID, nothing to do */
Rik van Riel6062a8d2013-04-30 19:15:44 -07002225 if (IS_ERR(sma)) {
2226 rcu_read_unlock();
Manfred Spraul380af1b2008-07-25 01:48:06 -07002227 continue;
Rik van Riel6062a8d2013-04-30 19:15:44 -07002228 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229
Rik van Riel6062a8d2013-04-30 19:15:44 -07002230 sem_lock(sma, NULL, -1);
Manfred Spraul6e224f92013-10-16 13:46:45 -07002231 /* exit_sem raced with IPC_RMID, nothing to do */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08002232 if (!ipc_valid_object(&sma->sem_perm)) {
Manfred Spraul6e224f92013-10-16 13:46:45 -07002233 sem_unlock(sma, -1);
2234 rcu_read_unlock();
2235 continue;
2236 }
Nick Pigginbf17bb72009-12-15 16:47:28 -08002237 un = __lookup_undo(ulp, semid);
Manfred Spraul380af1b2008-07-25 01:48:06 -07002238 if (un == NULL) {
2239 /* exit_sem raced with IPC_RMID+semget() that created
2240 * exactly the same semid. Nothing to do.
2241 */
Rik van Riel6062a8d2013-04-30 19:15:44 -07002242 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07002243 rcu_read_unlock();
Manfred Spraul380af1b2008-07-25 01:48:06 -07002244 continue;
2245 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246
Manfred Spraul380af1b2008-07-25 01:48:06 -07002247 /* remove un from the linked lists */
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -07002248 ipc_assert_locked_object(&sma->sem_perm);
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002249 list_del(&un->list_id);
2250
Herton R. Krzesinskia9795582015-08-14 15:35:05 -07002251 /* we are the last process using this ulp, acquiring ulp->lock
2252 * isn't required. Besides that, we are also protected against
2253 * IPC_RMID as we hold sma->sem_perm lock now
2254 */
Manfred Spraul380af1b2008-07-25 01:48:06 -07002255 list_del_rcu(&un->list_proc);
Manfred Spraul380af1b2008-07-25 01:48:06 -07002256
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002257 /* perform adjustments registered in un */
2258 for (i = 0; i < sma->sem_nsems; i++) {
Manfred Spraul1a233952017-07-12 14:34:38 -07002259 struct sem *semaphore = &sma->sems[i];
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002260 if (un->semadj[i]) {
2261 semaphore->semval += un->semadj[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -07002262 /*
2263 * Range checks of the new semaphore value,
2264 * not defined by sus:
2265 * - Some unices ignore the undo entirely
2266 * (e.g. HP UX 11i 11.22, Tru64 V5.1)
2267 * - some cap the value (e.g. FreeBSD caps
2268 * at 0, but doesn't enforce SEMVMX)
2269 *
2270 * Linux caps the semaphore value, both at 0
2271 * and at SEMVMX.
2272 *
Manfred Spraul239521f2014-01-27 17:07:04 -08002273 * Manfred <manfred@colorfullife.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -07002274 */
Ingo Molnar5f921ae2006-03-26 01:37:17 -08002275 if (semaphore->semval < 0)
2276 semaphore->semval = 0;
2277 if (semaphore->semval > SEMVMX)
2278 semaphore->semval = SEMVMX;
Pavel Emelyanovb4888932007-10-18 23:40:14 -07002279 semaphore->sempid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 }
2281 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 /* maybe some queued-up processes were waiting for this */
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002283 do_smart_update(sma, NULL, 0, 1, &wake_q);
Rik van Riel6062a8d2013-04-30 19:15:44 -07002284 sem_unlock(sma, -1);
Linus Torvalds6d49dab2013-05-03 15:04:40 -07002285 rcu_read_unlock();
Davidlohr Bueso9ae949f2016-12-14 15:06:34 -08002286 wake_up_q(&wake_q);
Manfred Spraul380af1b2008-07-25 01:48:06 -07002287
Lai Jiangshan693a8b62011-03-18 12:09:35 +08002288 kfree_rcu(un, rcu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289 }
Manfred Spraul4daa28f2008-07-25 01:48:04 -07002290 kfree(ulp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002291}
2292
2293#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07002294static int sysvipc_sem_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295{
Eric W. Biederman1efdb692012-02-07 16:54:11 -08002296 struct user_namespace *user_ns = seq_user_ns(s);
Kees Cookade9f912017-08-02 13:32:21 -07002297 struct kern_ipc_perm *ipcp = it;
2298 struct sem_array *sma = container_of(ipcp, struct sem_array, sem_perm);
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07002299 time64_t sem_otime;
Manfred Sprauld12e1e52013-07-08 16:01:25 -07002300
Manfred Sprauld8c63372013-09-30 13:45:07 -07002301 /*
2302 * The proc interface isn't aware of sem_lock(), it calls
2303 * ipc_lock_object() directly (in sysvipc_find_ipc).
Manfred Spraul5864a2f2016-10-11 13:54:50 -07002304 * In order to stay compatible with sem_lock(), we must
2305 * enter / leave complex_mode.
Manfred Sprauld8c63372013-09-30 13:45:07 -07002306 */
Manfred Spraul5864a2f2016-10-11 13:54:50 -07002307 complexmode_enter(sma);
Manfred Sprauld8c63372013-09-30 13:45:07 -07002308
Manfred Sprauld12e1e52013-07-08 16:01:25 -07002309 sem_otime = get_semotime(sma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002310
Joe Perches7f032d62015-04-15 16:17:54 -07002311 seq_printf(s,
Deepa Dinamanie54d02b2017-08-02 19:51:13 -07002312 "%10d %10d %4o %10u %5u %5u %5u %5u %10llu %10llu\n",
Joe Perches7f032d62015-04-15 16:17:54 -07002313 sma->sem_perm.key,
2314 sma->sem_perm.id,
2315 sma->sem_perm.mode,
2316 sma->sem_nsems,
2317 from_kuid_munged(user_ns, sma->sem_perm.uid),
2318 from_kgid_munged(user_ns, sma->sem_perm.gid),
2319 from_kuid_munged(user_ns, sma->sem_perm.cuid),
2320 from_kgid_munged(user_ns, sma->sem_perm.cgid),
2321 sem_otime,
2322 sma->sem_ctime);
2323
Manfred Spraul5864a2f2016-10-11 13:54:50 -07002324 complexmode_tryleave(sma);
2325
Joe Perches7f032d62015-04-15 16:17:54 -07002326 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327}
2328#endif