When unbinding a device on the host which was still attached on the
client, I got a NULL pointer dereference on the client. This turned out
to be due to kthread_stop() being called on an already dead kthread.
Here is how I was able to reproduce the problem:
server:# usbip bind -b 1-2
client:# usbip attach -h server -b 1-2
server:# usbip unbind -b 1-2
This patch fixes the problem by checking the kthread before attempting
to kill it, as it is done on the opposite side in
stub_shutdown_connection().
Signed-off-by: Tobias Klauser <tklauser@xxxxxxxxxx>
---
drivers/staging/usbip/vhci_hcd.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/usbip/vhci_hcd.c b/drivers/staging/usbip/vhci_hcd.c
index 359b464..fab8eeb 100644
--- a/drivers/staging/usbip/vhci_hcd.c
+++ b/drivers/staging/usbip/vhci_hcd.c
@@ -844,9 +844,9 @@ static void vhci_shutdown_connection(struct usbip_device *ud)
}
/* kill threads related to this sdev, if v.c. exists */
- if (vdev->ud.tcp_rx)
+ if (vdev->ud.tcp_rx && !task_is_dead(vdev->ud.tcp_rx))
kthread_stop(vdev->ud.tcp_rx);
- if (vdev->ud.tcp_tx)
+ if (vdev->ud.tcp_tx && !task_is_dead(vdev->ud.tcp_tx))
kthread_stop(vdev->ud.tcp_tx);
pr_info("stop threads\n");
--
1.7.5.4
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