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authorTristan Ye <tristan.ye@oracle.com>2010-09-10 10:16:33 +0800
committerJoel Becker <joel.becker@oracle.com>2010-09-10 09:19:30 -0700
commit228ac6357718df2d5c8d70210fa51b2225aab5ee (patch)
tree4aaf7f05d03a5757b6c128d433c220b55d89fd88 /fs/ocfs2
parent0f4da216b8c3c35c90ecd18e1899c6f125957c2b (diff)
downloadlinux-228ac6357718df2d5c8d70210fa51b2225aab5ee.tar.gz
Ocfs2: Handle empty list in lockres_seq_start() for dlmdebug.c
This patch tries to handle the case in which list 'dlm->tracking_list' is
empty, to avoid accessing an invalid pointer. It fixes the following oops:

http://oss.oracle.com/bugzilla/show_bug.cgi?id=1287

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Diffstat (limited to 'fs/ocfs2')
-rw-r--r--fs/ocfs2/dlm/dlmdebug.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 5efdd37dfe48..901ca52bf86b 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -636,8 +636,14 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
 	spin_lock(&dlm->track_lock);
 	if (oldres)
 		track_list = &oldres->tracking;
-	else
+	else {
 		track_list = &dlm->tracking_list;
+		if (list_empty(track_list)) {
+			dl = NULL;
+			spin_unlock(&dlm->track_lock);
+			goto bail;
+		}
+	}
 
 	list_for_each_entry(res, track_list, tracking) {
 		if (&res->tracking == &dlm->tracking_list)
@@ -660,6 +666,7 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
 	} else
 		dl = NULL;
 
+bail:
 	/* passed to seq_show */
 	return dl;
 }