From: Karsten Graul <kgraul@linux.ibm.com>
Date: Wed, 26 Feb 2020 17:52:46 +0100
Subject: net/smc: check for valid ib_client_data
Git-commit: a2f2ef4a54c0d97aa6a8386f4ff23f36ebb488cf
Patch-mainline: v5.6-rc4
References: git-fixes

In smc_ib_remove_dev() check if the provided ib device was actually
initialized for SMC before.

Reported-by: syzbot+84484ccebdd4e5451d91@syzkaller.appspotmail.com
Fixes: a4cf0443c414 ("smc: introduce SMC as an IB-client")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 net/smc/smc_ib.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -560,6 +560,8 @@ static void smc_ib_remove_dev(struct ib_
 	struct smc_ib_device *smcibdev;
 
 	smcibdev = ib_get_client_data(ibdev, &smc_ib_client);
+	if (!smcibdev || smcibdev->ibdev != ibdev)
+		return;
 	ib_set_client_data(ibdev, &smc_ib_client, NULL);
 	spin_lock(&smc_ib_devices.lock);
 	list_del_init(&smcibdev->list); /* remove from smc_ib_devices */