From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Nazarewicz Date: Tue, 12 Nov 2013 13:30:05 +0100 Subject: [Cluster-devel] [PATCH] gfs2: fix potential NULL pointer dereference Message-ID: <1384259405-7913-1-git-send-email-mpn@google.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Michal Nazarewicz Commit [e66cf1610: GFS2: Use lockref for glocks] replaced call: atomic_read(&gi->gl->gl_ref) == 0 with: __lockref_is_dead(&gl->gl_lockref) therefore changing how gl is accessed, from gi->gl to plan gl. However, gl can be a NULL pointer, and so gi->gl needs to be used instead (which is guaranteed not to be NULL because fo the while loop checking that condition). Signed-off-by: Michal Nazarewicz --- fs/gfs2/glock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index e66a800..c8420f7 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1899,7 +1899,8 @@ static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi) gi->nhash = 0; } /* Skip entries for other sb and dead entries */ - } while (gi->sdp != gi->gl->gl_sbd || __lockref_is_dead(&gl->gl_lockref)); + } while (gi->sdp != gi->gl->gl_sbd || + __lockref_is_dead(&gi->gl->gl_lockref)); return 0; } -- 1.8.4.1