linux/net/sunrpc
Trond Myklebust b2f21f7d85 SUNRPC: accept() may return sockets that are still in SYN_RECV
We're seeing traces of the following form:

 [10952.396347] svc: transport ffff88042ba4a 000 dequeued, inuse=2
 [10952.396351] svc: tcp_accept ffff88042ba4 a000 sock ffff88042a6e4c80
 [10952.396362] nfsd: connect from 10.2.6.1, port=187
 [10952.396364] svc: svc_setup_socket ffff8800b99bcf00
 [10952.396368] setting up TCP socket for reading
 [10952.396370] svc: svc_setup_socket created ffff8803eb10a000 (inet ffff88042b75b800)
 [10952.396373] svc: transport ffff8803eb10a000 put into queue
 [10952.396375] svc: transport ffff88042ba4a000 put into queue
 [10952.396377] svc: server ffff8800bb0ec000 waiting for data (to = 3600000)
 [10952.396380] svc: transport ffff8803eb10a000 dequeued, inuse=2
 [10952.396381] svc_recv: found XPT_CLOSE
 [10952.396397] svc: svc_delete_xprt(ffff8803eb10a000)
 [10952.396398] svc: svc_tcp_sock_detach(ffff8803eb10a000)
 [10952.396399] svc: svc_sock_detach(ffff8803eb10a000)
 [10952.396412] svc: svc_sock_free(ffff8803eb10a000)

i.e. an immediate close of the socket after initialisation.

The culprit appears to be the test at the end of svc_tcp_init, which
checks if the newly created socket is in the TCP_ESTABLISHED state,
and immediately closes it if not. The evidence appears to suggest that
the socket might still be in the SYN_RECV state at this time.

The fix is to check for both states, and then to add a check in
svc_tcp_state_change() to ensure we don't close the socket when
it transitions into TCP_ESTABLISHED.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
2016-08-01 17:53:41 -04:00
..
auth_gss sunrpc: add gss minor status to svcauth_gss_proxy_init 2016-07-13 15:40:46 -04:00
xprtrdma NFS client updates for Linux 4.7 2016-05-26 10:33:33 -07:00
addr.c replace strict_strto calls 2014-07-12 18:45:49 -04:00
auth_generic.c sunrpc: add rpc_lookup_generic_cred 2016-05-09 09:05:40 -04:00
auth_null.c nfsd: Lower NFSv4.1 callback message size limit 2016-03-01 13:06:35 -08:00
auth_unix.c sunrpc: plumb gfp_t parm into crcreate operation 2016-05-09 09:05:40 -04:00
auth.c SUNRPC: Ensure get_rpccred() and put_rpccred() can take NULL arguments 2016-05-17 15:48:06 -04:00
backchannel_rqst.c SUNRPC: Fix callback channel 2015-12-07 13:04:59 -08:00
cache.c sunrpc: remove 'inuse' flag from struct cache_detail. 2016-07-13 15:32:47 -04:00
clnt.c rpc: share one xps between all backchannels 2016-06-15 10:32:25 -04:00
debugfs.c SUNRPC: Address kbuild warning in net/sunrpc/debugfs.c 2015-06-11 14:01:06 -04:00
Kconfig rpcrdma: Merge svcrdma and xprtrdma modules into one 2015-06-04 16:56:02 -04:00
Makefile SUNRPC: Add a structure to track multiple transports 2016-02-05 18:48:54 -05:00
netns.h Merge branch 'for-3.14' of git://linux-nfs.org/~bfields/linux 2014-01-30 10:18:43 -08:00
rpc_pipe.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
rpcb_clnt.c SUNRPC: Use the multipath iterator to assign a transport to each task 2016-02-05 18:48:55 -05:00
sched.c SUNRPC: Allow caller to specify the transport to use 2016-02-05 18:48:55 -05:00
socklib.c sunrpc: do not pull udp headers on receive 2016-04-11 15:31:33 -04:00
stats.c sunrpc: add rpc_count_iostats_idx 2015-02-03 11:06:38 -08:00
sunrpc_syms.c sunrpc: make debugfs file creation failure non-fatal 2015-04-23 14:42:27 -04:00
sunrpc.h SUNRPC: track whether a request is coming from a loop-back interface. 2014-05-22 15:59:18 -04:00
svc_xprt.c SUNRPC: Remove unused callback xpo_adjust_wspace() 2016-07-13 15:53:50 -04:00
svc.c SUNRPC: Fix callback channel 2015-12-07 13:04:59 -08:00
svcauth_unix.c svcrpc: move some initialization to common code 2015-11-24 10:39:16 -07:00
svcauth.c svcrpc: move some initialization to common code 2015-11-24 10:39:16 -07:00
svcsock.c SUNRPC: accept() may return sockets that are still in SYN_RECV 2016-08-01 17:53:41 -04:00
sysctl.c Sunrpc: Supports hexadecimal number for sysctl files of sunrpc debug 2015-11-03 15:56:49 -05:00
timer.c net: cleanup unsigned to unsigned int 2012-04-15 12:44:40 -04:00
xdr.c SUNRPC: init xdr_stream for zero iov_len, page_len 2016-05-09 09:05:40 -04:00
xprt.c SUNRPC: Use the multipath iterator to assign a transport to each task 2016-02-05 18:48:55 -05:00
xprtmultipath.c SUNRPC: Add a structure to track multiple transports 2016-02-05 18:48:54 -05:00
xprtsock.c rpc: share one xps between all backchannels 2016-06-15 10:32:25 -04:00