Commit 5131a184 authored Jun 22, 2007 by Zach Brown Committed by Vlad Yasevich Jun 26, 2007

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>

parent 186e2343

net/sctp/socket.c

+4 −1

Original line number	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
		* 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()

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