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| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2014-02-11 09:15:54 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-03-06 22:06:20 -0800 |
| commit | a57401ef4a206089f2e075be65ca55b21c3ae209 (patch) | |
| tree | ef57e3e6ba61441e999d8c2dc33f403142bd103c | |
| parent | 89fe406b29aeeb32f7ff2116f084879f48bf19ce (diff) | |
| download | lwn-a57401ef4a206089f2e075be65ca55b21c3ae209.tar.gz lwn-a57401ef4a206089f2e075be65ca55b21c3ae209.zip | |
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.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index dd9d295813cf..cad4a95e7484 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -504,6 +504,7 @@ 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", @@ -521,7 +522,7 @@ 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); } @@ -531,6 +532,9 @@ 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; } |