From: Davidlohr Bueso <dave@stgolabs.net>
Date: Thu, 3 Jan 2019 23:27:12 +0000 (-0800)
Subject: fs/epoll: robustify ep->mtx held checks
X-Git-Tag: Ubuntu-5.13.0-19.19~9416^2~36
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=21877e1a5b520132f54515f8835c963056418b4c;p=mirror_ubuntu-jammy-kernel.git

fs/epoll: robustify ep->mtx held checks

Insted of just commenting how important it is, lets make it more robust
and add a lockdep_assert_held() call.

Link: http://lkml.kernel.org/r/20181108051006.18751-5-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jason Baron <jbaron@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index fb7f05f4099d..68e27d1cb5cd 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1637,6 +1637,8 @@ static __poll_t ep_send_events_proc(struct eventpoll *ep, struct list_head *head
 	 * Items cannot vanish during the loop because ep_scan_ready_list() is
 	 * holding "mtx" during this call.
 	 */
+	lockdep_assert_held(&ep->mtx);
+
 	list_for_each_entry_safe(epi, tmp, head, rdllink) {
 		if (esed->res >= esed->maxevents)
 			break;