SCTP: lock_sock_nested in sctp_sock_migrate
sctp_sock_migrate() grabs the socket lock on a newly allocated socket while
holding the socket lock on an old socket. lockdep worries that this might
be a recursive lock attempt.
task/3026 is trying to acquire lock:
(sk_lock-AF_INET){--..}, at: [<ffffffff88105b8c>] sctp_sock_migrate+0x2e3/0x327 [sctp]
but task is already holding lock:
(sk_lock-AF_INET){--..}, at: [<ffffffff8810891f>] sctp_accept+0xdf/0x1e3 [sctp]
This patch tells lockdep that this locking is safe by using
lock_sock_nested().
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 2fc0366..67861a8 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -6123,8 +6123,11 @@
* queued to the backlog. This prevents a potential race between
* backlog processing on the old socket and new-packet processing
* on the new socket.
+ *
+ * The caller has just allocated newsk so we can guarantee that other
+ * paths won't try to lock it and then oldsk.
*/
- sctp_lock_sock(newsk);
+ lock_sock_nested(newsk, SINGLE_DEPTH_NESTING);
sctp_assoc_migrate(assoc, newsk);
/* If the association on the newsk is already closed before accept()