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>
diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 5efdd37..901ca52 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -636,8 +636,14 @@
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 @@
} else
dl = NULL;
+bail:
/* passed to seq_show */
return dl;
}