svcrpc: sends on closed socket should stop immediately
authorJ. Bruce Fields <bfields@redhat.com>
Mon, 20 Aug 2012 20:04:40 +0000 (16:04 -0400)
committerJ. Bruce Fields <bfields@redhat.com>
Mon, 20 Aug 2012 22:38:59 +0000 (18:38 -0400)
svc_tcp_sendto sets XPT_CLOSE if we fail to transmit the entire reply.
However, the XPT_CLOSE won't be acted on immediately.  Meanwhile other
threads could send further replies before the socket is really shut
down.  This can manifest as data corruption: for example, if a truncated
read reply is followed by another rpc reply, that second reply will look
to the client like further read data.

Symptoms were data corruption preceded by svc_tcp_sendto logging
something like

kernel: rpc-srv/tcp: nfsd: sent only 963696 when sending 1048708 bytes - shutting down socket

Cc: stable@vger.kernel.org
Reported-by: Malahal Naineni <malahal@us.ibm.com>
Tested-by: Malahal Naineni <malahal@us.ibm.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
net/sunrpc/svc_xprt.c

index 88f2bf671960d444e73d3d9eba2998f75ac2885b..0d693a89434f4636f0c6a21b555999cc7c81c3a8 100644 (file)
@@ -794,7 +794,8 @@ int svc_send(struct svc_rqst *rqstp)
 
        /* Grab mutex to serialize outgoing data. */
        mutex_lock(&xprt->xpt_mutex);
-       if (test_bit(XPT_DEAD, &xprt->xpt_flags))
+       if (test_bit(XPT_DEAD, &xprt->xpt_flags)
+                       || test_bit(XPT_CLOSE, &xprt->xpt_flags))
                len = -ENOTCONN;
        else
                len = xprt->xpt_ops->xpo_sendto(rqstp);