ocfs2: fix NULL pointer dereference when traversing o2hb_all_regions
There may exist NULL pointer dereference in config_item_name() when one
volume (say Volume A) unmounts while another (say Volume B) mounting.
Volume A Volume B
already Mounted.
Unmounting, call
o2hb_heartbeat_group_drop_item()
-> config_item_put(item)
set reg(A)->item.ci_name to NULL
in function config_item_cleanup().
begin mounting, call
o2hb_region_pin() and tranverse all
regions. When reading
reg(A)->item.ci_name, it causes
NULL pointer dereference.
call o2hb_region_release() and
del reg(A) from list.
So we should skip accessing regions that is going to release when
tranverse o2hb_all_regions.
Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: joyce <xuejiufei@huawei.com>
Acked-by: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Sunil Mushran <sunil.mushran@gmail.com>
Cc: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 956d79d..5c1c864 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -2389,6 +2389,9 @@
assert_spin_locked(&o2hb_live_lock);
list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+ if (reg->hr_item_dropped)
+ continue;
+
uuid = config_item_name(®->hr_item);
/* local heartbeat */
@@ -2439,6 +2442,9 @@
assert_spin_locked(&o2hb_live_lock);
list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+ if (reg->hr_item_dropped)
+ continue;
+
uuid = config_item_name(®->hr_item);
if (region_uuid) {
if (strcmp(region_uuid, uuid))
@@ -2654,6 +2660,9 @@
p = region_uuids;
list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
+ if (reg->hr_item_dropped)
+ continue;
+
mlog(0, "Region: %s\n", config_item_name(®->hr_item));
if (numregs < max_regions) {
memcpy(p, config_item_name(®->hr_item),