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| author | Kirill Korotaev <dev@openvz.org> | 2006-12-10 02:20:11 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-10 09:55:42 -0800 |
| commit | 054b9108e01ef27e2e6b32b4226abb6024626f06 (patch) | |
| tree | be5c7a42f26f76406da51b888d8ae8e020ba7821 /kernel | |
| parent | 6711cab43ed5e60bf51e3dbbce6395e87d4e9805 (diff) | |
| download | linux-3.10-054b9108e01ef27e2e6b32b4226abb6024626f06.tar.gz linux-3.10-054b9108e01ef27e2e6b32b4226abb6024626f06.tar.bz2 linux-3.10-054b9108e01ef27e2e6b32b4226abb6024626f06.zip | |
[PATCH] move_task_off_dead_cpu() should be called with disabled ints
move_task_off_dead_cpu() requires interrupts to be disabled, while
migrate_dead() calls it with enabled interrupts. Added appropriate
comments to functions and added BUG_ON(!irqs_disabled()) into
double_rq_lock() and double_lock_balance() which are the origin sources of
such bugs.
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index a08387b5f7f..f04add905bd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1952,6 +1952,7 @@ static void double_rq_lock(struct rq *rq1, struct rq *rq2) __acquires(rq1->lock) __acquires(rq2->lock) { + BUG_ON(!irqs_disabled()); if (rq1 == rq2) { spin_lock(&rq1->lock); __acquire(rq2->lock); /* Fake it out ;) */ @@ -1991,6 +1992,11 @@ static void double_lock_balance(struct rq *this_rq, struct rq *busiest) __acquires(busiest->lock) __acquires(this_rq->lock) { + if (unlikely(!irqs_disabled())) { + /* printk() doesn't work good under rq->lock */ + spin_unlock(&this_rq->lock); + BUG_ON(1); + } if (unlikely(!spin_trylock(&busiest->lock))) { if (busiest < this_rq) { spin_unlock(&this_rq->lock); @@ -5067,7 +5073,10 @@ wait_to_die: } #ifdef CONFIG_HOTPLUG_CPU -/* Figure out where task on dead CPU should go, use force if neccessary. */ +/* + * Figure out where task on dead CPU should go, use force if neccessary. + * NOTE: interrupts should be disabled by the caller + */ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) { unsigned long flags; @@ -5187,6 +5196,7 @@ void idle_task_exit(void) mmdrop(mm); } +/* called under rq->lock with disabled interrupts */ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) { struct rq *rq = cpu_rq(dead_cpu); @@ -5203,10 +5213,11 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) * Drop lock around migration; if someone else moves it, * that's OK. No task can be added to this CPU, so iteration is * fine. + * NOTE: interrupts should be left disabled --dev@ */ - spin_unlock_irq(&rq->lock); + spin_unlock(&rq->lock); move_task_off_dead_cpu(dead_cpu, p); - spin_lock_irq(&rq->lock); + spin_lock(&rq->lock); put_task_struct(p); } |