From: Sasha Levin <sasha.levin@oracle.com>
Date: Tue, 1 Dec 2015 01:34:20 +0000 (-0500)
Subject: sched/core: Remove false-positive warning from wake_up_process()
X-Git-Tag: v2.6.32.70~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=788c44ff3dc52cc20cec88200bda758acb57cc66;p=thirdparty%2Fkernel%2Fstable.git

sched/core: Remove false-positive warning from wake_up_process()

commit 119d6f6a3be8b424b200dcee56e74484d5445f7e upstream.

Because wakeups can (fundamentally) be late, a task might not be in
the expected state. Therefore testing against a task's state is racy,
and can yield false positives.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: oleg@redhat.com
Fixes: 9067ac85d533 ("wake_up_process() should be never used to wakeup a TASK_STOPPED/TRACED task")
Link: http://lkml.kernel.org/r/1448933660-23082-1-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
(cherry picked from commit 0e796c1b57fdd97fc040b0b78ff7fea6c0a4a39d)
Signed-off-by: Willy Tarreau <w@1wt.eu>
---

diff --git a/kernel/sched.c b/kernel/sched.c
index 42bf6a668e91c..fe26b86cdbfcc 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2618,7 +2618,6 @@ out:
  */
 int wake_up_process(struct task_struct *p)
 {
-	WARN_ON(task_is_stopped_or_traced(p));
 	return try_to_wake_up(p, TASK_NORMAL, 0);
 }
 EXPORT_SYMBOL(wake_up_process);