Messages in this thread Patch in this message | | | Date | Wed, 03 Aug 2011 15:00:26 -0700 | From | Greg KH <> | Subject | [006/102] Staging: usbip: vhci-hcd: Do not kill already dead RX/TX kthread |
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3.0-stable review patch. If anyone has any objections, please let us know.
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From: Tobias Klauser <tklauser@distanz.ch>
commit 8547d4cc2b616e4f1dafebe2c673fc986422b506 upstream.
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@distanz.ch> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- drivers/staging/usbip/vhci_hcd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/staging/usbip/vhci_hcd.c +++ b/drivers/staging/usbip/vhci_hcd.c @@ -846,9 +846,9 @@ static void vhci_shutdown_connection(str } /* 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");
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