linux-kernel - [PATCH 4.19 011/243] autofs: fix a leak in autofs_expire

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Message-Id: <20191211150339.868438289@linuxfoundation.org>
Date:   Wed, 11 Dec 2019 16:02:53 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Al Viro <viro@...iv.linux.org.uk>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 011/243] autofs: fix a leak in autofs_expire_indirect()

From: Al Viro <viro@...iv.linux.org.uk>

[ Upstream commit 03ad0d703df75c43f78bd72e16124b5b94a95188 ]

if the second call of should_expire() in there ends up
grabbing and returning a new reference to dentry, we need
to drop it before continuing.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/autofs/expire.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/autofs/expire.c b/fs/autofs/expire.c
index 28d9c2b1b3bb3..70e9afe589fbf 100644
--- a/fs/autofs/expire.c
+++ b/fs/autofs/expire.c
@@ -501,9 +501,10 @@ static struct dentry *autofs_expire_indirect(struct super_block *sb,
 		 */
 		how &= ~AUTOFS_EXP_LEAVES;
 		found = should_expire(expired, mnt, timeout, how);
-		if (!found || found != expired)
-			/* Something has changed, continue */
+		if (found != expired) { // something has changed, continue
+			dput(found);
 			goto next;
+		}
 
 		if (expired != dentry)
 			dput(dentry);
-- 
2.20.1