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

net/sctp/socket.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -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()