Revert "lockdep: check that no locks held at freeze time"
This reverts commit 6aa9707099c4b25700940eb3d016f16c4434360d.
Commit 6aa9707099c4 ("lockdep: check that no locks held at freeze time")
causes problems with NFS root filesystems. The failures were noticed on
OMAP2 and 3 boards during kernel init:
[ BUG: swapper/0/1 still has locks held! ]
3.9.0-rc3-00344-ga937536 #1 Not tainted
-------------------------------------
1 lock held by swapper/0/1:
#0: (&type->s_umount_key#13/1){+.+.+.}, at: [<c011e84c>] sget+0x248/0x574
stack backtrace:
rpc_wait_bit_killable
__wait_on_bit
out_of_line_wait_on_bit
__rpc_execute
rpc_run_task
rpc_call_sync
nfs_proc_get_root
nfs_get_root
nfs_fs_mount_common
nfs_try_mount
nfs_fs_mount
mount_fs
vfs_kern_mount
do_mount
sys_mount
do_mount_root
mount_root
prepare_namespace
kernel_init_freeable
kernel_init
Although the rootfs mounts, the system is unstable. Here's a transcript
from a PM test:
http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt
Here's what the test log should look like:
http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt
Mailing list discussion is here:
http://lkml.org/lkml/2013/3/4/221
Deal with this for v3.9 by reverting the problem commit, until folks can
figure out the right long-term course of action.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: <maciej.rutecki@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
index a975de1..3bd46f7 100644
--- a/include/linux/debug_locks.h
+++ b/include/linux/debug_locks.h
@@ -51,7 +51,7 @@
extern void debug_show_all_locks(void);
extern void debug_show_held_locks(struct task_struct *task);
extern void debug_check_no_locks_freed(const void *from, unsigned long len);
-extern void debug_check_no_locks_held(void);
+extern void debug_check_no_locks_held(struct task_struct *task);
#else
static inline void debug_show_all_locks(void)
{
@@ -67,7 +67,7 @@
}
static inline void
-debug_check_no_locks_held(void)
+debug_check_no_locks_held(struct task_struct *task)
{
}
#endif
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index 043a5cf..e70df40 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -3,7 +3,6 @@
#ifndef FREEZER_H_INCLUDED
#define FREEZER_H_INCLUDED
-#include <linux/debug_locks.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/atomic.h>
@@ -49,8 +48,6 @@
static inline bool try_to_freeze(void)
{
- if (!(current->flags & PF_NOFREEZE))
- debug_check_no_locks_held();
might_sleep();
if (likely(!freezing(current)))
return false;
diff --git a/kernel/exit.c b/kernel/exit.c
index 51e485c..60bc027 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -835,7 +835,7 @@
/*
* Make sure we are holding no locks:
*/
- debug_check_no_locks_held();
+ debug_check_no_locks_held(tsk);
/*
* We can do this unlocked here. The futex code uses this flag
* just to verify whether the pi state cleanup has been done
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 259db20..8a0efac 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -4088,7 +4088,7 @@
}
EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
-static void print_held_locks_bug(void)
+static void print_held_locks_bug(struct task_struct *curr)
{
if (!debug_locks_off())
return;
@@ -4097,21 +4097,22 @@
printk("\n");
printk("=====================================\n");
- printk("[ BUG: %s/%d still has locks held! ]\n",
- current->comm, task_pid_nr(current));
+ printk("[ BUG: lock held at task exit time! ]\n");
print_kernel_ident();
printk("-------------------------------------\n");
- lockdep_print_held_locks(current);
+ printk("%s/%d is exiting with locks still held!\n",
+ curr->comm, task_pid_nr(curr));
+ lockdep_print_held_locks(curr);
+
printk("\nstack backtrace:\n");
dump_stack();
}
-void debug_check_no_locks_held(void)
+void debug_check_no_locks_held(struct task_struct *task)
{
- if (unlikely(current->lockdep_depth > 0))
- print_held_locks_bug();
+ if (unlikely(task->lockdep_depth > 0))
+ print_held_locks_bug(task);
}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
void debug_show_all_locks(void)
{