From: Karsten Graul <kgraul@linux.ibm.com>
Subject: net/smc: abort CLC connection in smc_release
Patch-mainline: v4.20-rc4
Git-commit: f07920ad9c6f5781c90ac4915f8254d999d8c1cc
References: FATE#325698, LTC#167867, bsc#1113481
Description: net/smc: bugfix and compatibility patches
Symptom: Random hangs in smc processing:
user space application hangs in socket send() or recv() call or
does never get a notification from a select() call.
Missing compatibility to other platforms:
confirm rkey and delete rkey processing is required by the
design, but delete rkey processing is missing. This leads to
protocol failures when communicating with other platforms like
zOS. The SMC-D shutdown signal support is missing, so there is
no detection if the remote peer closed the link group.
Broken administration of available WR send payload buffers due to
a use-after-free condition.
Problem: Misbehaviour regarding the user space api can lead to hang
situations. SMC is not fully compatible to some other platforms
due to missing rkey processing and SMC-D shutdown signal support.
Solution: Fixed protocoll deficiencies by implementing the required rkey
processing. For SMC-D, the cursors are now handled atomically to
handle parallel modifications. The SMC-D shutdown signal is now
processed when received and sent to the remote peer if needed.
Prereq patches are included.
Reproduction: Run SMC on a loaded system against zOS as peer system.
Upstream-Description:
net/smc: abort CLC connection in smc_release
In case of a non-blocking SMC socket, the initial CLC handshake is
performed over a blocking TCP connection in a worker. If the SMC socket
is released, smc_release has to wait for the blocking CLC socket
operations (e.g., kernel_connect) inside the worker.
This patch aborts a CLC connection when the respective non-blocking SMC
socket is released to avoid waiting on socket operations or timeouts.
Signed-off-by: Hans Wippel <hwippel@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
net/smc/af_smc.c | 2 ++
1 file changed, 2 insertions(+)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -127,6 +127,8 @@ static int smc_release(struct socket *so
smc = smc_sk(sk);
/* cleanup for a dangling non-blocking connect */
+ if (smc->connect_info && sk->sk_state == SMC_INIT)
+ tcp_abort(smc->clcsock->sk, ECONNABORTED);
flush_work(&smc->connect_work);
kfree(smc->connect_info);
smc->connect_info = NULL;