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authorKonstantin Khlebnikov <khlebnikov@openvz.org>2012-06-20 23:53:01 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-06-21 01:39:36 +0400
commit4fe7efdbdfb1c7e7a7f31decfd831c0f31d37091 (patch)
tree5d8fdf353ba3791ef10031ade2d93aa87aa179d3
parente0897d75f0b22e8c3a7287a48548c5686ef73447 (diff)
downloadlinux-4fe7efdbdfb1c7e7a7f31decfd831c0f31d37091.tar.xz
mm: correctly synchronize rss-counters at exit/exec
do_exit() and exec_mmap() call sync_mm_rss() before mm_release() does put_user(clear_child_tid) which can update task->rss_stat and thus make mm->rss_stat inconsistent. This triggers the "BUG:" printk in check_mm(). Let's fix this bug in the safest way, and optimize/cleanup this later. Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/exec.c2
-rw-r--r--kernel/exit.c1
2 files changed, 2 insertions, 1 deletions
diff --git a/fs/exec.c b/fs/exec.c
index a79786a8d2c8..da27b91ff1e8 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -819,10 +819,10 @@ static int exec_mmap(struct mm_struct *mm)
/* 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) {
+ sync_mm_rss(old_mm);
/*
* Make sure that if there is a core dump in progress
* for the old mm, we get out and die instead of going
diff --git a/kernel/exit.c b/kernel/exit.c
index 34867cc5b42a..c0277d3f1aaa 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -643,6 +643,7 @@ static void exit_mm(struct task_struct * tsk)
mm_release(tsk, mm);
if (!mm)
return;
+ sync_mm_rss(mm);
/*
* Serialize with any possible pending coredump.
* We must hold mmap_sem around checking core_state