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authorSowmini Varadhan <sowmini.varadhan@oracle.com>2017-11-30 11:11:29 -0800
committerDavid S. Miller <davem@davemloft.net>2017-12-01 15:25:15 -0500
commitf10b4cff98c6977668434fbf5dd58695eeca2897 (patch)
tree71350054376a576a62bafac64b96b601f1290d85 /net/rds
parent681648e67d43cf269c5590ecf021ed481f4551fc (diff)
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rds: tcp: atomically purge entries from rds_tcp_conn_list during netns delete
The rds_tcp_kill_sock() function parses the rds_tcp_conn_list to find the rds_connection entries marked for deletion as part of the netns deletion under the protection of the rds_tcp_conn_lock. Since the rds_tcp_conn_list tracks rds_tcp_connections (which have a 1:1 mapping with rds_conn_path), multiple tc entries in the rds_tcp_conn_list will map to a single rds_connection, and will be deleted as part of the rds_conn_destroy() operation that is done outside the rds_tcp_conn_lock. The rds_tcp_conn_list traversal done under the protection of rds_tcp_conn_lock should not leave any doomed tc entries in the list after the rds_tcp_conn_lock is released, else another concurrently executiong netns delete (for a differnt netns) thread may trip on these entries. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rds')
-rw-r--r--net/rds/tcp.c9
-rw-r--r--net/rds/tcp.h1
2 files changed, 8 insertions, 2 deletions
diff --git a/net/rds/tcp.c b/net/rds/tcp.c
index f580f72ae69e..39f502d47969 100644
--- a/net/rds/tcp.c
+++ b/net/rds/tcp.c
@@ -306,7 +306,8 @@ static void rds_tcp_conn_free(void *arg)
rdsdebug("freeing tc %p\n", tc);
spin_lock_irqsave(&rds_tcp_conn_lock, flags);
- list_del(&tc->t_tcp_node);
+ if (!tc->t_tcp_node_detached)
+ list_del(&tc->t_tcp_node);
spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
kmem_cache_free(rds_tcp_conn_slab, tc);
@@ -510,8 +511,12 @@ static void rds_tcp_kill_sock(struct net *net)
if (net != c_net || !tc->t_sock)
continue;
- if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
+ if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn)) {
list_move_tail(&tc->t_tcp_node, &tmp_list);
+ } else {
+ list_del(&tc->t_tcp_node);
+ tc->t_tcp_node_detached = true;
+ }
}
spin_unlock_irq(&rds_tcp_conn_lock);
list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
diff --git a/net/rds/tcp.h b/net/rds/tcp.h
index 1aafbf7c3011..e7858ee8ed8b 100644
--- a/net/rds/tcp.h
+++ b/net/rds/tcp.h
@@ -12,6 +12,7 @@ struct rds_tcp_incoming {
struct rds_tcp_connection {
struct list_head t_tcp_node;
+ bool t_tcp_node_detached;
struct rds_conn_path *t_cpath;
/* t_conn_path_lock synchronizes the connection establishment between
* rds_tcp_accept_one and rds_tcp_conn_path_connect