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From:   Davidlohr Bueso <dave@stgolabs.net>
To:     akpm@linux-foundation.org
Cc:     jbaron@akamai.com, viro@zeniv.linux.org.uk, dave@stgolabs.net,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Davidlohr Bueso <dbueso@suse.de>
Subject: [PATCH 4/6] fs/epoll: robustify ep->mtx held checks
Date:   Wed,  7 Nov 2018 21:10:04 -0800
Message-Id: <20181108051006.18751-5-dave@stgolabs.net>
In-Reply-To: <20181108051006.18751-1-dave@stgolabs.net>
References: <20181108051006.18751-1-dave@stgolabs.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
 fs/eventpoll.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 347da3f4f5d3..6a0c2591e57e 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;
-- 
2.16.4