This is a note to let you know that I've just added the patch titled
mm: correctly synchronize rss-counters at exit/exec
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-correctly-synchronize-rss-counters-at-exit-exec.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 4fe7efdbdfb1c7e7a7f31decfd831c0f31d37091 Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <[email protected]>
Date: Wed, 20 Jun 2012 12:53:01 -0700
Subject: mm: correctly synchronize rss-counters at exit/exec
From: Konstantin Khlebnikov <[email protected]>
commit 4fe7efdbdfb1c7e7a7f31decfd831c0f31d37091 upstream.
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 <[email protected]>
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/exec.c | 2 +-
kernel/exit.c | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -823,10 +823,10 @@ 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) {
+ 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
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -643,6 +643,7 @@ static void exit_mm(struct task_struct *
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
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/mm-correctly-synchronize-rss-counters-at-exit-exec.patch
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