From: David Howells <dhowells@redhat.com>
Date: Wed, 4 Apr 2018 12:41:26 +0000 (+0100)
Subject: fscache: Detect multiple relinquishment of a cookie
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d0fb31ecda2c3c6092d0c2a46a6a72653e7dcabb;p=openwrt%2Fstaging%2Fblogic.git

fscache: Detect multiple relinquishment of a cookie

Report if an fscache cookie is relinquished multiple times by the netfs.

Signed-off-by: David <dhowells@redhat.com>
---

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index d705125665f0..98d22f495cd8 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -602,7 +602,8 @@ void __fscache_relinquish_cookie(struct fscache_cookie *cookie, bool retire)
 	       atomic_read(&cookie->n_active), retire);
 
 	/* No further netfs-accessing operations on this cookie permitted */
-	set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags);
+	if (test_and_set_bit(FSCACHE_COOKIE_RELINQUISHED, &cookie->flags))
+		BUG();
 
 	__fscache_disable_cookie(cookie, retire);