From 228ac6357718df2d5c8d70210fa51b2225aab5ee Mon Sep 17 00:00:00 2001 From: Tristan Ye Date: Fri, 10 Sep 2010 10:16:33 +0800 Subject: [PATCH] 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 Signed-off-by: Joel Becker --- fs/ocfs2/dlm/dlmdebug.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) 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; }