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authorOleg Nesterov <oleg@tv-sign.ru>2007-05-23 13:57:27 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-23 20:14:11 -0700
commita076e4bca2fdabb9e45d86722cc72c0944da5f94 (patch)
treeb11684f4b39dabb84584773f1b7811b5207e7f01 /kernel/kthread.c
parent49b12d4f5e274517b8bc032d507abf31cc2f4150 (diff)
freezer: fix kthread_create vs freezer theoretical race
kthread() sleeps in TASK_INTERRUPTIBLE state waiting for the first wakeup. In theory, this wakeup may come from freeze_process()->signal_wake_up(), so the task can disappear even before kthread_create() sets its ->comm. Change kthread() to use TASK_UNINTERRUPTIBLE. [akpm@linux-foundation.org: s/BUG_ON/WARN_ON+recover] Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/kthread.c')
-rw-r--r--kernel/kthread.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index df8a8e8f6ca..bbd51b81a3e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -70,7 +70,7 @@ static int kthread(void *_create)
data = create->data;
/* OK, tell user we're spawned, wait for stop or wakeup */
- __set_current_state(TASK_INTERRUPTIBLE);
+ __set_current_state(TASK_UNINTERRUPTIBLE);
complete(&create->started);
schedule();
@@ -162,7 +162,10 @@ EXPORT_SYMBOL(kthread_create);
*/
void kthread_bind(struct task_struct *k, unsigned int cpu)
{
- BUG_ON(k->state != TASK_INTERRUPTIBLE);
+ if (k->state != TASK_UNINTERRUPTIBLE) {
+ WARN_ON(1);
+ return;
+ }
/* Must have done schedule() in kthread() before we set_task_cpu */
wait_task_inactive(k);
set_task_cpu(k, cpu);