posix timers: timer_delete: remove the bogus "->it_process != NULL" check

RFC New Oliver Pinter 1 participant 1 message Aug 2, 2008

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Oliver Pinter

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2008-08-02 21:41 UTC #0 lore raw

RFC 1/1 posix timers: timer_delete: remove the bogus "->it_process != NULL" check

It is an RFC for sending this patch for stable, when this patch needed, then send ACK and CC stable, if not then send NAK.

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Quoted 1 line

From 4b7a1304267bff68260ae861784b27130e805be3 Mon Sep 17 00:00:00 2001

From: Oleg Nesterov <[email protected]>
Date: Fri, 25 Jul 2008 01:47:26 -0700
Subject: [PATCH] posix timers: timer_delete: remove the bogus "->it_process != NULL" check

[ Upstream commit 4b7a1304267bff68260ae861784b27130e805be3 ]

sys_timer_delete() and itimer_delete() check "timer->it_process != NULL", this looks completely bogus. ->it_process == NULL means that this timer is already under destruction or it is not fully initialized, this must not happen.

	sys_timer_delete: the timer is locked, and lock_timer() can't succeed
	if ->it_process == NULL.

	itimer_delete: it is called by exit_itimers() when there are no other
	threads which can play with signal_struct->posix_timers.

Signed-off-by Oleg Nesterov <[email protected]>

Acked-by Roland McGrath <[email protected]>

Cc john stultz <[email protected]>

Cc Thomas Gleixner <[email protected]>

Cc Roland McGrath <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

Signed-off-by Linus Torvalds <[email protected]>

CC Oliver Pinter <[email protected]>

kernel/posix-timers.c +8 ~~-10~~

index dbd8398..17f5326 100644
@@ -856,11 +856,10 @@ retry_delete:
 	 * This keeps any tasks waiting on the spin lock from thinking
 	 * they got something (see the lock code above).
 	 */
-	if (timer->it_process) {
-		if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-			put_task_struct(timer->it_process);
-		timer->it_process = NULL;
-	}
+	if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+		put_task_struct(timer->it_process);
+	timer->it_process = NULL;
+
 	unlock_timer(timer, flags);
 	release_posix_timer(timer, IT_ID_SET);
 	return 0;

@@ -885,11 +884,10 @@ retry_delete:
 	 * This keeps any tasks waiting on the spin lock from thinking
 	 * they got something (see the lock code above).
 	 */
-	if (timer->it_process) {
-		if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
-			put_task_struct(timer->it_process);
-		timer->it_process = NULL;
-	}
+	if (timer->it_sigev_notify == (SIGEV_SIGNAL|SIGEV_THREAD_ID))
+		put_task_struct(timer->it_process);
+	timer->it_process = NULL;
+
 	unlock_timer(timer, flags);
 	release_posix_timer(timer, IT_ID_SET);
 }