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authorTrond Myklebust <trond.myklebust@primarydata.com>2014-02-11 09:15:54 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-03-06 21:30:08 -0800
commit830d5bd83a895818388f874675d3bd76dc470e01 (patch)
tree362e1cb333d48a211da3492c7dab71b88e47ea20
parent6319b13bb7e47c75e00cb6a5cabfb448983dc233 (diff)
downloadlinux-linaro-stable-830d5bd83a895818388f874675d3bd76dc470e01.tar.gz
SUNRPC: Fix races in xs_nospace()
commit 06ea0bfe6e6043cb56a78935a19f6f8ebc636226 upstream. When a send failure occurs due to the socket being out of buffer space, we call xs_nospace() in order to have the RPC task wait until the socket has drained enough to make it worth while trying again. The current patch fixes a race in which the socket is drained before we get round to setting up the machinery in xs_nospace(), and which is reported to cause hangs. Link: http://lkml.kernel.org/r/20140210170315.33dfc621@notabene.brown Fixes: a9a6b52ee1ba (SUNRPC: Don't start the retransmission timer...) Reported-by: Neil Brown <neilb@suse.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/sunrpc/xprtsock.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 8a0e04d0928a..fc47165dc254 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -502,6 +502,7 @@ static int xs_nospace(struct rpc_task *task)
struct rpc_rqst *req = task->tk_rqstp;
struct rpc_xprt *xprt = req->rq_xprt;
struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+ struct sock *sk = transport->inet;
int ret = -EAGAIN;
dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
@@ -519,7 +520,7 @@ static int xs_nospace(struct rpc_task *task)
* window size
*/
set_bit(SOCK_NOSPACE, &transport->sock->flags);
- transport->inet->sk_write_pending++;
+ sk->sk_write_pending++;
/* ...and wait for more buffer space */
xprt_wait_for_buffer_space(task, xs_nospace_callback);
}
@@ -529,6 +530,9 @@ static int xs_nospace(struct rpc_task *task)
}
spin_unlock_bh(&xprt->transport_lock);
+
+ /* Race breaker in case memory is freed before above code is called */
+ sk->sk_write_space(sk);
return ret;
}