nvme_fc_unregister_remote removes the remote port on a lport object at
any point in time when there is no active association. This races with
with the reconnect logic, because nvme_fc_create_association is not
taking a lock to check the port_state and atomically increase the
active count on the rport.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/all/u4ttvhnn7lark5w3sgrbuy2rxupcvosp4qmvj46nwzgeo5ausc@uyrkdls2muwx
Signed-off-by: Daniel Wagner <wagi@kernel.org>
---
 drivers/nvme/host/fc.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index 3e12d4683ac72f9ef9c6dff64d22d5d97e6f3d60..03987f497a5b55533ee169c9a7cb9b479d0f2d92 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -3032,11 +3032,17 @@ nvme_fc_create_association(struct nvme_fc_ctrl *ctrl)
 
 	++ctrl->ctrl.nr_reconnects;
 
-	if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE)
+	spin_lock_irqsave(&ctrl->rport->lock, flags);
+	if (ctrl->rport->remoteport.port_state != FC_OBJSTATE_ONLINE) {
+		spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 		return -ENODEV;
+	}
 
-	if (nvme_fc_ctlr_active_on_rport(ctrl))
+	if (nvme_fc_ctlr_active_on_rport(ctrl)) {
+		spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 		return -ENOTUNIQ;
+	}
+	spin_unlock_irqrestore(&ctrl->rport->lock, flags);
 
 	dev_info(ctrl->ctrl.device,
 		"NVME-FC{%d}: create association : host wwpn 0x%016llx "

-- 
2.51.0

On 9/2/25 12:22, Daniel Wagner wrote:
> nvme_fc_unregister_remote removes the remote port on a lport object at
> any point in time when there is no active association. This races with
> with the reconnect logic, because nvme_fc_create_association is not
> taking a lock to check the port_state and atomically increase the
> active count on the rport.
> 
> Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
> Closes: https://lore.kernel.org/all/u4ttvhnn7lark5w3sgrbuy2rxupcvosp4qmvj46nwzgeo5ausc@uyrkdls2muwx
> Signed-off-by: Daniel Wagner <wagi@kernel.org>
> ---
>   drivers/nvme/host/fc.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich