Commit 5131a184 authored by Zach Brown's avatar Zach Brown Committed by Vlad Yasevich

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: default avatarZach Brown <zach.brown@oracle.com>
Signed-off-by: default avatarVlad Yasevich <vladislav.yasevich@hp.com>
parent 186e2343
...@@ -6123,8 +6123,11 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk, ...@@ -6123,8 +6123,11 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
* queued to the backlog. This prevents a potential race between * queued to the backlog. This prevents a potential race between
* backlog processing on the old socket and new-packet processing * backlog processing on the old socket and new-packet processing
* on the new socket. * 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); sctp_assoc_migrate(assoc, newsk);
/* If the association on the newsk is already closed before accept() /* If the association on the newsk is already closed before accept()
......
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