3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: alex chen alex.chen@huawei.com
commit 853bc26a7ea39e354b9f8889ae7ad1492ffa28d2 upstream.
The subsystem.su_mutex is required while accessing the item->ci_parent, otherwise, NULL pointer dereference to the item->ci_parent will be triggered in the following situation:
add node delete node sys_write vfs_write configfs_write_file o2nm_node_store o2nm_node_local_write do_rmdir vfs_rmdir configfs_rmdir mutex_lock(&subsys->su_mutex); unlink_obj item->ci_group = NULL; item->ci_parent = NULL; to_o2nm_cluster_from_node node->nd_item.ci_parent->ci_parent BUG since of NULL pointer dereference to nd_item.ci_parent
Moreover, the o2nm_cluster also should be protected by the subsystem.su_mutex.
[alex.chen@huawei.com: v2] Link: http://lkml.kernel.org/r/59EEAA69.9080703@huawei.com Link: http://lkml.kernel.org/r/59E9B36A.10700@huawei.com Signed-off-by: Alex Chen alex.chen@huawei.com Reviewed-by: Jun Piao piaojun@huawei.com Reviewed-by: Joseph Qi jiangqi903@gmail.com Cc: Mark Fasheh mfasheh@versity.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ocfs2/cluster/nodemanager.c | 63 +++++++++++++++++++++++++++++----- 1 file changed, 55 insertions(+), 8 deletions(-)
--- a/fs/ocfs2/cluster/nodemanager.c +++ b/fs/ocfs2/cluster/nodemanager.c @@ -40,6 +40,9 @@ char *o2nm_fence_method_desc[O2NM_FENCE_ "panic", /* O2NM_FENCE_PANIC */ };
+static inline void o2nm_lock_subsystem(void); +static inline void o2nm_unlock_subsystem(void); + struct o2nm_node *o2nm_get_node_by_num(u8 node_num) { struct o2nm_node *node = NULL; @@ -181,7 +184,10 @@ static struct o2nm_cluster *to_o2nm_clus { /* through the first node_set .parent * mycluster/nodes/mynode == o2nm_cluster->o2nm_node_group->o2nm_node */ - return to_o2nm_cluster(node->nd_item.ci_parent->ci_parent); + if (node->nd_item.ci_parent) + return to_o2nm_cluster(node->nd_item.ci_parent->ci_parent); + else + return NULL; }
enum { @@ -194,7 +200,7 @@ enum { static ssize_t o2nm_node_num_write(struct o2nm_node *node, const char *page, size_t count) { - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; unsigned long tmp; char *p = (char *)page;
@@ -213,6 +219,13 @@ static ssize_t o2nm_node_num_write(struc !test_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes)) return -EINVAL; /* XXX */
+ o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + o2nm_unlock_subsystem(); + return -EINVAL; + } + write_lock(&cluster->cl_nodes_lock); if (cluster->cl_nodes[tmp]) p = NULL; @@ -222,6 +235,8 @@ static ssize_t o2nm_node_num_write(struc set_bit(tmp, cluster->cl_nodes_bitmap); } write_unlock(&cluster->cl_nodes_lock); + o2nm_unlock_subsystem(); + if (p == NULL) return -EEXIST;
@@ -261,7 +276,7 @@ static ssize_t o2nm_node_ipv4_address_wr const char *page, size_t count) { - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; int ret, i; struct rb_node **p, *parent; unsigned int octets[4]; @@ -278,6 +293,13 @@ static ssize_t o2nm_node_ipv4_address_wr be32_add_cpu(&ipv4_addr, octets[i] << (i * 8)); }
+ o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + o2nm_unlock_subsystem(); + return -EINVAL; + } + ret = 0; write_lock(&cluster->cl_nodes_lock); if (o2nm_node_ip_tree_lookup(cluster, ipv4_addr, &p, &parent)) @@ -287,6 +309,8 @@ static ssize_t o2nm_node_ipv4_address_wr rb_insert_color(&node->nd_ip_node, &cluster->cl_node_ip_tree); } write_unlock(&cluster->cl_nodes_lock); + o2nm_unlock_subsystem(); + if (ret) return ret;
@@ -303,7 +327,7 @@ static ssize_t o2nm_node_local_read(stru static ssize_t o2nm_node_local_write(struct o2nm_node *node, const char *page, size_t count) { - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); + struct o2nm_cluster *cluster; unsigned long tmp; char *p = (char *)page; ssize_t ret; @@ -321,17 +345,26 @@ static ssize_t o2nm_node_local_write(str !test_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes)) return -EINVAL; /* XXX */
+ o2nm_lock_subsystem(); + cluster = to_o2nm_cluster_from_node(node); + if (!cluster) { + ret = -EINVAL; + goto out; + } + /* the only failure case is trying to set a new local node * when a different one is already set */ if (tmp && tmp == cluster->cl_has_local && - cluster->cl_local_node != node->nd_num) - return -EBUSY; + cluster->cl_local_node != node->nd_num) { + ret = -EBUSY; + goto out; + }
/* bring up the rx thread if we're setting the new local node. */ if (tmp && !cluster->cl_has_local) { ret = o2net_start_listening(node); if (ret) - return ret; + goto out; }
if (!tmp && cluster->cl_has_local && @@ -346,7 +379,11 @@ static ssize_t o2nm_node_local_write(str cluster->cl_local_node = node->nd_num; }
- return count; + ret = count; + +out: + o2nm_unlock_subsystem(); + return ret; }
struct o2nm_node_attribute { @@ -889,6 +926,16 @@ static struct o2nm_cluster_group o2nm_cl }, };
+static inline void o2nm_lock_subsystem(void) +{ + mutex_lock(&o2nm_cluster_group.cs_subsys.su_mutex); +} + +static inline void o2nm_unlock_subsystem(void) +{ + mutex_unlock(&o2nm_cluster_group.cs_subsys.su_mutex); +} + int o2nm_depend_item(struct config_item *item) { return configfs_depend_item(&o2nm_cluster_group.cs_subsys, item);