Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d6e971d8 authored by Jeff Layton's avatar Jeff Layton Committed by Trond Myklebust
Browse files

sunrpc: lock xprt before trying to set memalloc on the sockets 



It's possible that we could race with a call to xs_reset_transport, in
which case the xprt->inet pointer could be zeroed out while we're
accessing it. Lock the xprt before we try to set memalloc on it.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: default avatarJeff Layton <jeff.layton@primarydata.com>
Reviewed-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 264d1df3

net/sunrpc/xprtsock.c

+27 −8
Original line number Original line Diff line number Diff line
@@ -1959,11 +1959,22 @@ static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task) 
}

}





#if IS_ENABLED(CONFIG_SUNRPC_SWAP)

#if IS_ENABLED(CONFIG_SUNRPC_SWAP)

/*

 * Note that this should be called with XPRT_LOCKED held (or when we otherwise

 * know that we have exclusive access to the socket), to guard against

 * races with xs_reset_transport.

 */

static void xs_set_memalloc(struct rpc_xprt *xprt)

static void xs_set_memalloc(struct rpc_xprt *xprt)

{

{

	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,

	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,

			xprt);

			xprt);





	/*

	 * If there's no sock, then we have nothing to set. The

	 * reconnecting process will get it for us.

	 */

	if (!transport->inet)

		return;

	if (atomic_read(&xprt->swapper))

	if (atomic_read(&xprt->swapper))

		sk_set_memalloc(transport->inet);

		sk_set_memalloc(transport->inet);

}

}
@@ -1978,11 +1989,15 @@ static void xs_set_memalloc(struct rpc_xprt *xprt) 
int

int

xs_swapper_enable(struct rpc_xprt *xprt)

xs_swapper_enable(struct rpc_xprt *xprt)

{

{

	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,

	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);

			xprt);





	if (atomic_inc_return(&xprt->swapper) == 1)

	if (atomic_inc_return(&xprt->swapper) != 1)

		sk_set_memalloc(transport->inet);

		return 0;

	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))

		return -ERESTARTSYS;

	if (xs->inet)

		sk_set_memalloc(xs->inet);

	xprt_release_xprt(xprt, NULL);

	return 0;

	return 0;

}

}
@@ -1996,11 +2011,15 @@ xs_swapper_enable(struct rpc_xprt *xprt) 
void

void

xs_swapper_disable(struct rpc_xprt *xprt)

xs_swapper_disable(struct rpc_xprt *xprt)

{

{

	struct sock_xprt *transport = container_of(xprt, struct sock_xprt,

	struct sock_xprt *xs = container_of(xprt, struct sock_xprt, xprt);

			xprt);





	if (atomic_dec_and_test(&xprt->swapper))

	if (!atomic_dec_and_test(&xprt->swapper))

		sk_clear_memalloc(transport->inet);

		return;

	if (wait_on_bit_lock(&xprt->state, XPRT_LOCKED, TASK_KILLABLE))

		return;

	if (xs->inet)

		sk_clear_memalloc(xs->inet);

	xprt_release_xprt(xprt, NULL);

}

}

#else

#else

static void xs_set_memalloc(struct rpc_xprt *xprt)

static void xs_set_memalloc(struct rpc_xprt *xprt)