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>
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