From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752140Ab1IXRal (ORCPT ); Sat, 24 Sep 2011 13:30:41 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:48729 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752101Ab1IXRaj (ORCPT ); Sat, 24 Sep 2011 13:30:39 -0400 From: Manfred Spraul To: LKML Cc: Thomas Gleixner , Mike Galbraith , Peter Zijlstra , Manfred Spraul Subject: [PATCH 2/3] ipc/sem.c: handle spurious wakeups Date: Sat, 24 Sep 2011 19:37:11 +0200 Message-Id: <1316885831-11996-1-git-send-email-manfred@colorfullife.com> X-Mailer: git-send-email 1.7.6 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org semtimedop() does not handle spurious wakeups, it returns -EINTR to user space. Most other schedule() users would just loop and not return to user space. The patch adds such a loop to semtimedop() Reported-by: Peter Zijlstra Signed-off-by: Manfred Spraul --- ipc/sem.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/ipc/sem.c b/ipc/sem.c index fb13be1..227948f 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -1426,6 +1426,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, queue.status = -EINTR; queue.sleeper = current; + +sleep_again: current->state = TASK_INTERRUPTIBLE; sem_unlock(sma); @@ -1478,6 +1480,13 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops, */ if (timeout && jiffies_left == 0) error = -EAGAIN; + + /* + * If the wakeup was spurious, just retry + */ + if (error == -EINTR && !signal_pending(current)) + goto sleep_again; + unlink_queue(sma, &queue); out_unlock_free: -- 1.7.6