[PATCH AUTOSEL 3.18 07/41] ocfs2: fix a panic problem caused by o2cb_ctl

Sasha Levin
2019-03-27T18:25:39Z

From: Jia Guo <guojia12@huawei.com>

[ Upstream commit cc725ef3cb202ef2019a3c67c8913efa05c3cce6 ]

In the process of creating a node, it will cause NULL pointer
dereference in kernel if o2cb_ctl failed in the interval (mkdir,
o2cb_set_node_attribute(node_num)] in function o2cb_add_node.

The node num is initialized to 0 in function o2nm_node_group_make_item,
o2nm_node_group_drop_item will mistake the node number 0 for a valid
node number when we delete the node before the node number is set
correctly. If the local node number of the current host happens to be
0, cluster->cl_local_node will be set to O2NM_INVALID_NODE_NUM while
o2hb_thread still running. The panic stack is generated as follows:

o2hb_thread
\-o2hb_do_disk_heartbeat
\-o2hb_check_own_slot
|-slot = &reg->hr_slots[o2nm_this_node()];
//o2nm_this_node() return O2NM_INVALID_NODE_NUM

We need to check whether the node number is set when we delete the node.

Link: http://lkml.kernel.org/r/133d8045-72cc-863e-8eae-5013f9f6bc51@huawei.com
Signed-off-by: Jia Guo <guojia12@huawei.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ocfs2/cluster/nodemanager.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c
index 441c84e169e6..059414bb19dc 100644
--- a/fs/ocfs2/cluster/nodemanager.c
+++ b/fs/ocfs2/cluster/nodemanager.c
@@ -721,13 +721,15 @@ static void o2nm_node_group_drop_item(struct config_group *group,
struct o2nm_node *node = to_o2nm_node(item);
struct o2nm_cluster *cluster = to_o2nm_cluster(group->cg_item.ci_parent);

- o2net_disconnect_node(node);
+ if (cluster->cl_nodes[node->nd_num] == node) {
+ o2net_disconnect_node(node);

- if (cluster->cl_has_local &&
- (cluster->cl_local_node == node->nd_num)) {
- cluster->cl_has_local = 0;
- cluster->cl_local_node = O2NM_INVALID_NODE_NUM;
- o2net_stop_listening(node);
+ if (cluster->cl_has_local &&
+ (cluster->cl_local_node == node->nd_num)) {
+ cluster->cl_has_local = 0;
+ cluster->cl_local_node = O2NM_INVALID_NODE_NUM;
+ o2net_stop_listening(node);
+ }
}

/* XXX call into net to stop this node from trading messages */
--
2.19.1