From d5b36a4dbd06c5e8e36ca8ccc552f679069e2946 Mon Sep 17 00:00:00 2001
From: Oleg Nesterov <oleg@redhat.com>
Date: Mon, 11 Jul 2022 18:16:25 +0200
Subject: fix race between exit_itimers() and /proc/pid/timers

As Chris explains, the comment above exit_itimers() is not correct,
we can race with proc_timers_seq_ops. Change exit_itimers() to clear
signal->posix_timers with ->siglock held.

Cc: <stable@vger.kernel.org>
Reported-by: chris@accessvector.net
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/exec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/exec.c')

diff --git a/fs/exec.c b/fs/exec.c
index 0989fb8472a1..778123259e42 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1301,7 +1301,7 @@ int begin_new_exec(struct linux_binprm * bprm)
 	bprm->mm = NULL;
 
 #ifdef CONFIG_POSIX_TIMERS
-	exit_itimers(me->signal);
+	exit_itimers(me);
 	flush_itimer_signals();
 #endif
 
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