[PATCH 5.4 122/123] net/smc: check for valid ib_client_data

[Greg Kroah-Hartman]

From: Karsten Graul <kgraul@xxxxxxxxxxxxx>

commit a2f2ef4a54c0d97aa6a8386f4ff23f36ebb488cf upstream.

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

Reported-by: syzbot+84484ccebdd4e5451d91@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: a4cf0443c414 ("smc: introduce SMC as an IB-client")
Signed-off-by: Karsten Graul <kgraul@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 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 */