Commit a28bf136 authored Mar 30, 2020 by Eric W. Biederman

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>

parent 13c432b5

fs/exec.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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