Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755871Ab2EXKgb (ORCPT ); Thu, 24 May 2012 06:36:31 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:54159 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755202Ab2EXKg3 (ORCPT ); Thu, 24 May 2012 06:36:29 -0400 Message-ID: <4FBE0F23.3080903@openvz.org> Date: Thu, 24 May 2012 14:36:19 +0400 From: Konstantin Khlebnikov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.2) Gecko/20120217 Firefox/10.0.2 Iceape/2.7.2 MIME-Version: 1.0 To: Martin Mokrejs CC: Andrew Morton , LKML , "markus@trippelsdorf.de" , "hughd@google.com" , "kamezawa.hiroyu@jp.fujitsu.com" , "oleg@redhat.com" , Michal Hocko , "linux-mm@kvack.org" Subject: Re: 3.4-rc7: BUG: Bad rss-counter state mm:ffff88040b56f800 idx:1 val:-59 References: <4FBC1618.5010408@fold.natur.cuni.cz> <20120522162835.c193c8e0.akpm@linux-foundation.org> <4FBD18A2.9060803@fold.natur.cuni.cz> In-Reply-To: <4FBD18A2.9060803@fold.natur.cuni.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5928 Lines: 162 Martin Mokrejs wrote: > Hi, > I rebooted the laptop twice today after just brief uses and the messages did not > appear in the logs. > > Now I just applied the below patch and during two reboots it did not appear either. > Do I have to use the computer for some longer while to reproduce the issue? ;-) Yes, some data must be in swap to reproduce this, so memory pressure required here. > > I will stay with the patch applied over 3.4-rc7 and would the BUG: re-appear I will > let you know. But I doubt at the moment I could confirm it really helped. > Clues how to reproduce? ;) > Martin > > Andrew Morton wrote: >> On Wed, 23 May 2012 00:41:28 +0200 >> Martin Mokrejs wrote: >> >>> Hi Andrew, >>> while shutting down my laptop (Dell Vostro 3550 with 16GB RAM, core i7) with 3.4-rc7 I got: >>> >>> May 23 00:07:54 vostro kernel: [352687.968267] BUG: Bad rss-counter state mm:ffff88040b56f800 idx:1 val:-59 >>> May 23 00:07:54 vostro kernel: [352687.968312] BUG: Bad rss-counter state mm:ffff88040b56f800 idx:2 val:59 >>> May 23 00:07:55 vostro acpid: exiting >>> May 23 00:07:55 vostro syslog-ng[2838]: syslog-ng shutting down; version='3.3.4' >>> >>> I found by Google the below thread and thought that maybe it is related? >>> http://comments.gmane.org/gmane.linux.kernel.mm/76459 >>> >>> ... >>> >> >> >> Well hopefully the below will fix this? >> >> I notice that I don't have this tagged for -stable backporting. That >> seems wrong. Konstantin, do we know for how long this bug has been in >> there? >> >> >> >> From: Konstantin Khlebnikov >> Subject: mm: correctly synchronize rss-counters at exit/exec >> >> mm->rss_stat counters have per-task delta: task->rss_stat. Before >> changing task->mm pointer the kernel must flush this delta with >> sync_mm_rss(). >> >> do_exit() already calls sync_mm_rss() to flush the rss-counters before >> committing the rss statistics into task->signal->maxrss, taskstats, audit >> and other stuff. Unfortunately the kernel does this before calling >> mm_release(), which can call put_user() for processing >> task->clear_child_tid. So at this point we can trigger page-faults and >> task->rss_stat becomes non-zero again. As a result mm->rss_stat becomes >> inconsistent and check_mm() will print something like this: >> >> | BUG: Bad rss-counter state mm:ffff88020813c380 idx:1 val:-1 >> | BUG: Bad rss-counter state mm:ffff88020813c380 idx:2 val:1 >> >> This patch moves sync_mm_rss() into mm_release(), and moves mm_release() >> out of do_exit() and calls it earlier. After mm_release() there should be >> no pagefaults. >> >> [akpm@linux-foundation.org: tweak comment] >> Signed-off-by: Konstantin Khlebnikov >> Reported-by: Markus Trippelsdorf >> Cc: Hugh Dickins >> Cc: KAMEZAWA Hiroyuki >> Cc: Oleg Nesterov >> Signed-off-by: Andrew Morton >> --- >> >> fs/exec.c | 1 - >> kernel/exit.c | 13 ++++++++----- >> kernel/fork.c | 8 ++++++++ >> 3 files changed, 16 insertions(+), 6 deletions(-) >> >> diff -puN fs/exec.c~mm-correctly-synchronize-rss-counters-at-exit-exec fs/exec.c >> --- a/fs/exec.c~mm-correctly-synchronize-rss-counters-at-exit-exec >> +++ a/fs/exec.c >> @@ -823,7 +823,6 @@ static int exec_mmap(struct mm_struct *m >> /* Notify parent that we're no longer interested in the old VM */ >> tsk = current; >> old_mm = current->mm; >> - sync_mm_rss(old_mm); >> mm_release(tsk, old_mm); >> >> if (old_mm) { >> diff -puN kernel/exit.c~mm-correctly-synchronize-rss-counters-at-exit-exec kernel/exit.c >> --- a/kernel/exit.c~mm-correctly-synchronize-rss-counters-at-exit-exec >> +++ a/kernel/exit.c >> @@ -423,6 +423,7 @@ void daemonize(const char *name, ...) >> * user space pages. We don't need them, and if we didn't close them >> * they would be locked into memory. >> */ >> + mm_release(current, current->mm); >> exit_mm(current); >> /* >> * We don't want to get frozen, in case system-wide hibernation >> @@ -640,7 +641,6 @@ static void exit_mm(struct task_struct * >> struct mm_struct *mm = tsk->mm; >> struct core_state *core_state; >> >> - mm_release(tsk, mm); >> if (!mm) >> return; >> /* >> @@ -959,9 +959,13 @@ void do_exit(long code) >> preempt_count()); >> >> acct_update_integrals(tsk); >> - /* sync mm's RSS info before statistics gathering */ >> - if (tsk->mm) >> - sync_mm_rss(tsk->mm); >> + >> + /* Set exit_code before complete_vfork_done() in mm_release() */ >> + tsk->exit_code = code; >> + >> + /* Release mm and sync mm's RSS info before statistics gathering */ >> + mm_release(tsk, tsk->mm); >> + >> group_dead = atomic_dec_and_test(&tsk->signal->live); >> if (group_dead) { >> hrtimer_cancel(&tsk->signal->real_timer); >> @@ -974,7 +978,6 @@ void do_exit(long code) >> tty_audit_exit(); >> audit_free(tsk); >> >> - tsk->exit_code = code; >> taskstats_exit(tsk, group_dead); >> >> exit_mm(tsk); >> diff -puN kernel/fork.c~mm-correctly-synchronize-rss-counters-at-exit-exec kernel/fork.c >> --- a/kernel/fork.c~mm-correctly-synchronize-rss-counters-at-exit-exec >> +++ a/kernel/fork.c >> @@ -809,6 +809,14 @@ void mm_release(struct task_struct *tsk, >> } >> tsk->clear_child_tid = NULL; >> } >> + >> + /* >> + * Final rss-counter synchronization. After this point there must be >> + * no pagefaults into this mm from the current context. Otherwise >> + * mm->rss_stat will be inconsistent. >> + */ >> + if (mm) >> + sync_mm_rss(mm); >> } >> >> /* >> _ >> >> . >> -- 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/