Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759406Ab1DNS4i (ORCPT ); Thu, 14 Apr 2011 14:56:38 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:44223 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759378Ab1DNS4g (ORCPT ); Thu, 14 Apr 2011 14:56:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=nueJmJTuV2KhFm+6nyd+0MRC5cYX1wuwvy3FfNwGEqO2Jux/PKqUPN6brg0NiaKmz6 9XKFN/RP3RijFmjWOJYMNuK97iHYGFLEgB5PiIPesUlAp1lZogXaJb/n9kFMRJlWrShs vCzuv4AEVqZ5XN6+J3ScHpIqrjOu90bxXl4vY= Subject: Re: [PATCH V2] futex: set FLAGS_HAS_TIMEOUT during demux for FUTEX_WAIT From: Eric Dumazet To: Darren Hart Cc: Linux Kernel Mailing List , Thomas Gleixner , Peter Zijlstra , Ingo Molnar , John Kacur In-Reply-To: <6aed1a53d080a90672bd44b773079dd81ac90b50.1302806742.git.dvhart@linux.intel.com> References: <1302800949.3248.42.camel@edumazet-laptop> <6aed1a53d080a90672bd44b773079dd81ac90b50.1302806742.git.dvhart@linux.intel.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 14 Apr 2011 20:56:31 +0200 Message-ID: <1302807391.2744.6.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2368 Lines: 69 Le jeudi 14 avril 2011 à 11:45 -0700, Darren Hart a écrit : > The FLAGS_HAS_TIMEOUT flag was not getting set, causing the restart_block to > restart futex_wait() without a timeout after a signal. > > Commit b41277dc7a18ee332d in 2.6.38 introduced the regression by accidentally > removing the the FLAGS_HAS_TIMEOUT assignment from futex_wait() during the setup > of the restart block. It makes more sense to set the flag earlier during > do_futex() where the other flags are set, although futex_wait is the only user > of FLAGS_HAS_TIMEOUT as it is the only op using a relative timeout (an > unfortunately preexisting condition). > > Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=32922 > > V2: Added references to commit message. > > Signed-off-by: Darren Hart > Reported-by: Tim Smith > Reported-by: Torsten Hilbrich > Cc: Thomas Gleixner > Cc: Peter Zijlstra > Cc: Ingo Molnar > CC: Eric Dumazet > CC: John Kacur > --- > kernel/futex.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/kernel/futex.c b/kernel/futex.c > index bda4157..6eac6b6 100644 > --- a/kernel/futex.c > +++ b/kernel/futex.c > @@ -2589,6 +2589,9 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout, > return -ENOSYS; > } > > + if (timeout) > + flags |= FLAGS_HAS_TIMEOUT; > + > switch (cmd) { > case FUTEX_WAIT: > val3 = FUTEX_BITSET_MATCH_ANY; I dont agree with your fix. You add yet another test in futex fastpath. Prior commit b41277dc7a18ee332d, this was done only in case of restart. Could we instead use diff --git a/kernel/futex.c b/kernel/futex.c index dfb924f..fe28dc2 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1886,7 +1886,7 @@ retry: restart->futex.val = val; restart->futex.time = abs_time->tv64; restart->futex.bitset = bitset; - restart->futex.flags = flags; + restart->futex.flags = flags | FLAGS_HAS_TIMEOUT; ret = -ERESTART_RESTARTBLOCK; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/