[PATCH] work around ppc64 bootup bug by making mutex-debugging save/restore irqs
It seems ppc64 wants to lock mutexes in early bootup code, with interrupts
disabled, and they expect interrupts to stay disabled, else they crash.
Work around this bug by making mutex debugging variants save/restore irq
flags.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c
index f4913c3..036b628 100644
--- a/kernel/mutex-debug.c
+++ b/kernel/mutex-debug.c
@@ -153,13 +153,13 @@
continue;
count++;
cursor = curr->next;
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
printk("\n#%03d: ", count);
printk_lock(lock, filter ? 0 : 1);
goto next;
}
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
printk("\n");
}
@@ -316,7 +316,7 @@
continue;
list_del_init(curr);
DEBUG_OFF();
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
printk("BUG: %s/%d, lock held at task exit time!\n",
task->comm, task->pid);
@@ -325,7 +325,7 @@
printk("exiting task is not even the owner??\n");
return;
}
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
}
/*
@@ -352,7 +352,7 @@
continue;
list_del_init(curr);
DEBUG_OFF();
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
printk("BUG: %s/%d, active lock [%p(%p-%p)] freed!\n",
current->comm, current->pid, lock, from, to);
@@ -362,7 +362,7 @@
printk("freeing task is not even the owner??\n");
return;
}
- debug_spin_lock_restore(&debug_mutex_lock, flags);
+ debug_spin_unlock_restore(&debug_mutex_lock, flags);
}
/*
diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
index fd38405..a5196c3 100644
--- a/kernel/mutex-debug.h
+++ b/kernel/mutex-debug.h
@@ -46,21 +46,6 @@
extern void debug_mutex_unlock(struct mutex *lock);
extern void debug_mutex_init(struct mutex *lock, const char *name);
-#define debug_spin_lock(lock) \
- do { \
- local_irq_disable(); \
- if (debug_mutex_on) \
- spin_lock(lock); \
- } while (0)
-
-#define debug_spin_unlock(lock) \
- do { \
- if (debug_mutex_on) \
- spin_unlock(lock); \
- local_irq_enable(); \
- preempt_check_resched(); \
- } while (0)
-
#define debug_spin_lock_save(lock, flags) \
do { \
local_irq_save(flags); \
@@ -68,7 +53,7 @@
spin_lock(lock); \
} while (0)
-#define debug_spin_lock_restore(lock, flags) \
+#define debug_spin_unlock_restore(lock, flags) \
do { \
if (debug_mutex_on) \
spin_unlock(lock); \
@@ -76,20 +61,20 @@
preempt_check_resched(); \
} while (0)
-#define spin_lock_mutex(lock) \
+#define spin_lock_mutex(lock, flags) \
do { \
struct mutex *l = container_of(lock, struct mutex, wait_lock); \
\
DEBUG_WARN_ON(in_interrupt()); \
- debug_spin_lock(&debug_mutex_lock); \
+ debug_spin_lock_save(&debug_mutex_lock, flags); \
spin_lock(lock); \
DEBUG_WARN_ON(l->magic != l); \
} while (0)
-#define spin_unlock_mutex(lock) \
+#define spin_unlock_mutex(lock, flags) \
do { \
spin_unlock(lock); \
- debug_spin_unlock(&debug_mutex_lock); \
+ debug_spin_unlock_restore(&debug_mutex_lock, flags); \
} while (0)
#define DEBUG_OFF() \
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 5449b21..7043db2 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -125,10 +125,11 @@
struct task_struct *task = current;
struct mutex_waiter waiter;
unsigned int old_val;
+ unsigned long flags;
debug_mutex_init_waiter(&waiter);
- spin_lock_mutex(&lock->wait_lock);
+ spin_lock_mutex(&lock->wait_lock, flags);
debug_mutex_add_waiter(lock, &waiter, task->thread_info, ip);
@@ -157,7 +158,7 @@
if (unlikely(state == TASK_INTERRUPTIBLE &&
signal_pending(task))) {
mutex_remove_waiter(lock, &waiter, task->thread_info);
- spin_unlock_mutex(&lock->wait_lock);
+ spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
return -EINTR;
@@ -165,9 +166,9 @@
__set_task_state(task, state);
/* didnt get the lock, go to sleep: */
- spin_unlock_mutex(&lock->wait_lock);
+ spin_unlock_mutex(&lock->wait_lock, flags);
schedule();
- spin_lock_mutex(&lock->wait_lock);
+ spin_lock_mutex(&lock->wait_lock, flags);
}
/* got the lock - rejoice! */
@@ -178,7 +179,7 @@
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);
- spin_unlock_mutex(&lock->wait_lock);
+ spin_unlock_mutex(&lock->wait_lock, flags);
debug_mutex_free_waiter(&waiter);
@@ -203,10 +204,11 @@
__mutex_unlock_slowpath(atomic_t *lock_count __IP_DECL__)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
DEBUG_WARN_ON(lock->owner != current_thread_info());
- spin_lock_mutex(&lock->wait_lock);
+ spin_lock_mutex(&lock->wait_lock, flags);
/*
* some architectures leave the lock unlocked in the fastpath failure
@@ -231,7 +233,7 @@
debug_mutex_clear_owner(lock);
- spin_unlock_mutex(&lock->wait_lock);
+ spin_unlock_mutex(&lock->wait_lock, flags);
}
/*
@@ -276,9 +278,10 @@
static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
{
struct mutex *lock = container_of(lock_count, struct mutex, count);
+ unsigned long flags;
int prev;
- spin_lock_mutex(&lock->wait_lock);
+ spin_lock_mutex(&lock->wait_lock, flags);
prev = atomic_xchg(&lock->count, -1);
if (likely(prev == 1))
@@ -287,7 +290,7 @@
if (likely(list_empty(&lock->wait_list)))
atomic_set(&lock->count, 0);
- spin_unlock_mutex(&lock->wait_lock);
+ spin_unlock_mutex(&lock->wait_lock, flags);
return prev == 1;
}
diff --git a/kernel/mutex.h b/kernel/mutex.h
index 00fe84e..0691899 100644
--- a/kernel/mutex.h
+++ b/kernel/mutex.h
@@ -9,8 +9,10 @@
* !CONFIG_DEBUG_MUTEXES case. Most of them are NOPs:
*/
-#define spin_lock_mutex(lock) spin_lock(lock)
-#define spin_unlock_mutex(lock) spin_unlock(lock)
+#define spin_lock_mutex(lock, flags) \
+ do { spin_lock(lock); (void)(flags); } while (0)
+#define spin_unlock_mutex(lock, flags) \
+ do { spin_unlock(lock); (void)(flags); } while (0)
#define mutex_remove_waiter(lock, waiter, ti) \
__list_del((waiter)->list.prev, (waiter)->list.next)