svcrpc: sends on closed socket should stop immediately
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>
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 88f2bf6..0d693a8 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -794,7 +794,8 @@
/* 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);