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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-05-23 13:57:27 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-23 20:14:11 -0700 |
| commit | a076e4bca2fdabb9e45d86722cc72c0944da5f94 (patch) | |
| tree | b11684f4b39dabb84584773f1b7811b5207e7f01 /kernel/kthread.c | |
| parent | 49b12d4f5e274517b8bc032d507abf31cc2f4150 (diff) | |
| download | lwn-a076e4bca2fdabb9e45d86722cc72c0944da5f94.tar.gz lwn-a076e4bca2fdabb9e45d86722cc72c0944da5f94.zip | |
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.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index df8a8e8f6ca4..bbd51b81a3e8 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); |