diff options
| author | Sowmini Varadhan <sowmini.varadhan@oracle.com> | 2017-11-30 20:11:29 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-01 21:25:15 +0100 |
| commit | f10b4cff98c6977668434fbf5dd58695eeca2897 (patch) | |
| tree | 71350054376a576a62bafac64b96b601f1290d85 /net/rds | |
| parent | rds: tcp: correctly sequence cleanup on netns deletion. (diff) | |
| download | linux-f10b4cff98c6977668434fbf5dd58695eeca2897.tar.xz linux-f10b4cff98c6977668434fbf5dd58695eeca2897.zip | |
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.c | 9 | ||||
| -rw-r--r-- | net/rds/tcp.h | 1 |
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 |