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? ;-) 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 <mmokrejs@xxxxxxxxxxxxxxxxxx> 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 <khlebnikov@xxxxxxxxxx> > 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@xxxxxxxxxxxxxxxxxxxx: tweak comment] > Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> > Reported-by: Markus Trippelsdorf <markus@xxxxxxxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > Cc: Oleg Nesterov <oleg@xxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>