On Wed, Apr 27, 2016 at 11:16:05AM +0900, Nobuo Iwata wrote:
> This patch adds a code fragment to ignore completing URBs in closing
> connection.
>
> Regarding this patch, 2 execution contexts are related.
>
> 1) stub_tx.c: stub_complete() which is called from USB core
> 1-1) add to unlink list and free URB or
> 1-2) move to tx list
>
> 2) stub_dev.c: stub_shutdown_connection() which is invoked by unbind
> operation through sysfs.
> 2-1) stop TX/RX threads
> 2-2) close TCP connection and set ud.tcp_socket to NULL
> 2-3) cleanup pending URBs by stub_device_cleanup_urbs(sdev)
> 2-4) free unlink list (no lock)
>
> In the race condition, URBs which will be cleared in 2-3) may be
> handled in 1).
> In case 1-1), it will not be transferred bcause tx threads are stooped
> in 2-1).
> In case 1-2), may be freed in 2-4).
>
> With this patch, after 2-2), completing URBs in 1) will not be handled
> and cleared in 2-3).
>
> The kernel log with this patch is as below.
>
> kernel: usbip_core: usbip_kernel_unlink:792: shutting down tcp_socket
> ef61d980
> kernel: usbip-host 1-3: free sdev f5df6180
> kernel: usbip-host 1-3: free urb f5df6700
> kernel: usbip-host 1-3: Enter
> kernel: usbip_core: usbip_stop_eh:132: usbip_eh waiting completion 5
> kernel: usbip_host: stub_complete:71: complete! status 0
> kernel: usbip_host: stub_complete:102: ignore urb for closed connection
> e725fc00 (*)
> kernel: usbip_host: stub_complete:71: complete! status -2
> kernel: usbip-host 1-3: stopped by a call to usb_kill_urb() because of
> cleaning up a virtual connection
> kernel: usbip-host 1-3: free urb e725fc00 (**)
> kernel: usbip-host 1-3: free urb e725e000
> kernel: usbip_host: stub_complete:71: complete! status -2
> kernel: usbip-host 1-3: stopped by a call to usb_kill_urb() because of
> cleaning up a virtual connection
> kernel: usbip-host 1-3: free urb e725f800
> kernel: usbip_host: stub_complete:71: complete! status -2
> kernel: usbip-host 1-3: stopped by a call to usb_kill_urb() because of
> cleaning up a virtual connection
> kernel: usbip-host 1-3: free urb e725e800
> kernel: usbip_host: stub_complete:71: complete! status -2
> kernel: usbip-host 1-3: stopped by a call to usb_kill_urb() because of
> cleaning up a virtual connection
> kernel: usbip-host 1-3: device reset
> kernel: usbip-host 1-3: lock for reset
> kernel: usbip_host: store_match_busid:178: del busid 1-3
> kernel: uvcvideo: Found UVC 1.00 device Venus USB2.0 Camera (056e:700a)
> kernel: input: Venus USB2.0 Camera as
> /devices/pci0000:00/0000:00:1a.7/usb1/1-3/1-3:1.0/input/input22
>
> (*) skipped with this patch in completion
> (**) released in 2-3
>
> A. version info
>
> v2)
> # Changed log level of ignore message from info to debug.
No you didn't:
> # Updated log capture in changelog with the log level modification.
>
> Signed-off-by: Nobuo Iwata <nobuo.iwata@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/usbip/stub_tx.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/usbip/stub_tx.c b/drivers/usb/usbip/stub_tx.c
> index dbcabc9..a4efc5a 100644
> --- a/drivers/usb/usbip/stub_tx.c
> +++ b/drivers/usb/usbip/stub_tx.c
> @@ -97,7 +97,11 @@ void stub_complete(struct urb *urb)
>
> /* link a urb to the queue of tx. */
> spin_lock_irqsave(&sdev->priv_lock, flags);
> - if (priv->unlinking) {
> + if (sdev->ud.tcp_socket == NULL) {
> + dev_info(&urb->dev->dev,
> + "ignore urb for closed connection %p", urb);
See?
And please put the "version information" below the --- line so it
doesn't show up in the changelog in the kernel tree when committed.
thanks,
greg k-h
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