mm: correctly synchronize rss-counters at exit/exec
authorKonstantin Khlebnikov <khlebnikov@openvz.org>
Wed, 20 Jun 2012 19:53:01 +0000 (12:53 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 20 Jun 2012 21:39:36 +0000 (14:39 -0700)
commit4fe7efdbdfb1c7e7a7f31decfd831c0f31d37091
tree5d8fdf353ba3791ef10031ade2d93aa87aa179d3
parente0897d75f0b22e8c3a7287a48548c5686ef73447
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>
fs/exec.c
kernel/exit.c