[PATCH net] net/smc: cancel event worker during device removal

[Karsten Graul <kgraul@linux.ibm.com>]

During IB device removal, cancel the event worker before the device
structure is freed. In the worker, check if the device is being
terminated and do not proceed with the event work in that case.

Fixes: a4cf0443c414 ("smc: introduce SMC as an IB-client")
Reported-by: syzbot+b297c6825752e7a07272@syzkaller.appspotmail.com
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
---
 net/smc/smc_ib.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index d6ba186f67e2..5e4e64a9aa4b 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -240,6 +240,9 @@ static void smc_ib_port_event_work(struct work_struct *work)
 		work, struct smc_ib_device, port_event_work);
 	u8 port_idx;
 
+	if (list_empty(&smcibdev->list))
+		return;
+
 	for_each_set_bit(port_idx, &smcibdev->port_event_mask, SMC_MAX_PORTS) {
 		smc_ib_remember_port_attr(smcibdev, port_idx + 1);
 		clear_bit(port_idx, &smcibdev->port_event_mask);
@@ -582,6 +585,7 @@ static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
 	smc_smcr_terminate_all(smcibdev);
 	smc_ib_cleanup_per_ibdev(smcibdev);
 	ib_unregister_event_handler(&smcibdev->event_handler);
+	cancel_work_sync(&smcibdev->port_event_work);
 	kfree(smcibdev);
 }
 
-- 
2.17.1