From a076e4bca2fdabb9e45d86722cc72c0944da5f94 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Wed, 23 May 2007 13:57:27 -0700 Subject: [PATCH] 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 Acked-by: "Eric W. Biederman" Signed-off-by: Rafael J. Wysocki Cc: Gautham R Shenoy Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kthread.c | 7 +++++-- 1 file 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);