Hi Joseph, On 2017/10/23 10:59, Joseph Qi wrote: > Hi Alex, > > On 17/10/20 16:27, alex chen wrote: >> 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. >> > Looks good to me. One suggestion is, we'd better add some blank lines > for code readability.
Thanks for your suggestions, i will send the patch v2. Thanks Alex > >> Signed-off-by: Alex Chen <[email protected]> >> Reviewed-by: Jun Piao <[email protected]> >> >> --- >> fs/ocfs2/cluster/nodemanager.c | 58 >> ++++++++++++++++++++++++++++++++++-------- >> 1 file changed, 48 insertions(+), 10 deletions(-) >> >> diff --git a/fs/ocfs2/cluster/nodemanager.c b/fs/ocfs2/cluster/nodemanager.c >> index b17d180..9b1859a 100644 >> --- a/fs/ocfs2/cluster/nodemanager.c >> +++ b/fs/ocfs2/cluster/nodemanager.c >> @@ -39,6 +39,8 @@ >> "reset", /* O2NM_FENCE_RESET */ >> "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) >> { >> @@ -181,7 +183,10 @@ static struct o2nm_cluster >> *to_o2nm_cluster_from_node(struct o2nm_node *node) >> { >> /* 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 +199,7 @@ static ssize_t o2nm_node_num_store(struct config_item >> *item, const char *page, >> size_t count) >> { >> struct o2nm_node *node = to_o2nm_node(item); >> - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); >> + struct o2nm_cluster *cluster; >> unsigned long tmp; >> char *p = (char *)page; >> int ret = 0; >> @@ -213,6 +218,12 @@ static ssize_t o2nm_node_num_store(struct config_item >> *item, const char *page, >> if (!test_bit(O2NM_NODE_ATTR_ADDRESS, &node->nd_set_attributes) || >> !test_bit(O2NM_NODE_ATTR_PORT, &node->nd_set_attributes)) >> return -EINVAL; /* XXX */ > <<< A blank line here may be better. > >> + 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]) >> @@ -226,6 +237,7 @@ static ssize_t o2nm_node_num_store(struct config_item >> *item, const char *page, >> set_bit(tmp, cluster->cl_nodes_bitmap); >> } >> write_unlock(&cluster->cl_nodes_lock); >> + o2nm_unlock_subsystem(); >> if (ret) >> return ret; >> >> @@ -269,7 +281,7 @@ static ssize_t o2nm_node_ipv4_address_store(struct >> config_item *item, >> size_t count) >> { >> struct o2nm_node *node = to_o2nm_node(item); >> - 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]; >> @@ -285,7 +297,12 @@ static ssize_t o2nm_node_ipv4_address_store(struct >> config_item *item, >> return -ERANGE; >> be32_add_cpu(&ipv4_addr, octets[i] << (i * 8)); >> } >> - > <<< Also here. > >> + 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)) >> @@ -298,6 +315,7 @@ static ssize_t o2nm_node_ipv4_address_store(struct >> config_item *item, >> 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; >> >> @@ -315,7 +333,7 @@ static ssize_t o2nm_node_local_store(struct config_item >> *item, const char *page, >> size_t count) >> { >> struct o2nm_node *node = to_o2nm_node(item); >> - struct o2nm_cluster *cluster = to_o2nm_cluster_from_node(node); >> + struct o2nm_cluster *cluster; >> unsigned long tmp; >> char *p = (char *)page; >> ssize_t ret; >> @@ -333,17 +351,24 @@ static ssize_t o2nm_node_local_store(struct >> config_item *item, const char *page, >> !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; >> + } > <<< Also here. > >> /* 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; >> + } > <<< Also here. > >> /* 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 && >> @@ -357,8 +382,11 @@ static ssize_t o2nm_node_local_store(struct config_item >> *item, const char *page, >> cluster->cl_has_local = tmp; >> cluster->cl_local_node = node->nd_num; >> } >> + ret = count; >> >> - return count; >> +out: >> + o2nm_unlock_subsystem(); >> + return ret; >> } >> >> CONFIGFS_ATTR(o2nm_node_, num); >> @@ -738,6 +766,16 @@ static void o2nm_cluster_group_drop_item(struct >> config_group *group, struct conf >> }, >> }; >> >> +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); >> > > . > _______________________________________________ Ocfs2-devel mailing list [email protected] https://oss.oracle.com/mailman/listinfo/ocfs2-devel
