From: Greg KH <[email protected]> 3.4-stable review patch. If anyone has any objections, please let me know.
------------------ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
