exec: Run sync_mm_rss before taking exec_update_mutex

Like exec_mm_release sync_mm_rss is about flushing out the state of
the old_mm, which does not need to happen under exec_update_mutex.

Make this explicit by moving sync_mm_rss outside of exec_update_mutex.

Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/875zd66za3.fsf_-_@x220.int.ebiederm.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2020-03-30 16:33:39 -05:00
parent 13c432b514
commit a28bf136e6

View File

@ -1051,13 +1051,14 @@ static int exec_mmap(struct mm_struct *mm)
tsk = current;
old_mm = current->mm;
exec_mm_release(tsk, old_mm);
if (old_mm)
sync_mm_rss(old_mm);
ret = mutex_lock_killable(&tsk->signal->exec_update_mutex);
if (ret)
return ret;
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