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Commit 4bc1e68e authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Prevent races in xs_abort_connection() 



The call to xprt_disconnect_done() that is triggered by a successful
connection reset will trigger another automatic wakeup of all tasks
on the xprt->pending rpc_wait_queue. In particular it will cause an
early wake up of the task that called xprt_connect().

All we really want to do here is clear all the socket-specific state
flags, so we split that functionality out of xs_sock_mark_closed()
into a helper that can be called by xs_abort_connection()

Reported-by: default avatarChris Perl <chris.perl@gmail.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: default avatarChris Perl <chris.perl@gmail.com>
parent b9d2bb2e

net/sunrpc/xprtsock.c

+8 −5
Original line number Diff line number Diff line
@@ -1453,7 +1453,7 @@ static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt) 
	xprt_clear_connecting(xprt);

}



static void xs_sock_mark_closed(struct rpc_xprt *xprt)

static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)

{

	smp_mb__before_clear_bit();

	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
@@ -1461,6 +1461,11 @@ static void xs_sock_mark_closed(struct rpc_xprt *xprt) 
	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);

	clear_bit(XPRT_CLOSING, &xprt->state);

	smp_mb__after_clear_bit();

}



static void xs_sock_mark_closed(struct rpc_xprt *xprt)

{

	xs_sock_reset_connection_flags(xprt);

	/* Mark transport as closed and wake up all pending tasks */

	xprt_disconnect_done(xprt);

}
@@ -2051,10 +2056,8 @@ static void xs_abort_connection(struct sock_xprt *transport) 
	any.sa_family = AF_UNSPEC;

	result = kernel_connect(transport->sock, &any, sizeof(any), 0);

	if (!result)

		xs_sock_mark_closed(&transport->xprt);

	else

		dprintk("RPC:       AF_UNSPEC connect return code %d\n",

				result);

		xs_sock_reset_connection_flags(&transport->xprt);

	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);

}



static void xs_tcp_reuse_connection(struct sock_xprt *transport)