From: Anirudh Rayabharam mail@anirudhrb.com
[ Upstream commit 258c81b341c8025d79073ce2d6ce19dcdc7d10d2 ]
In vhci_device_unlink_cleanup(), the URBs for unsent unlink requests are not given back. This sometimes causes usb_kill_urb to wait indefinitely for that urb to be given back. syzbot has reported a hung task issue [1] for this.
To fix this, give back the urbs corresponding to unsent unlink requests (unlink_tx list) similar to how urbs corresponding to unanswered unlink requests (unlink_rx list) are given back.
[1]: https://syzkaller.appspot.com/bug?id=08f12df95ae7da69814e64eb5515d5a85ed06b7...
Reported-by: syzbot+74d6ef051d3d2eacf428@syzkaller.appspotmail.com Tested-by: syzbot+74d6ef051d3d2eacf428@syzkaller.appspotmail.com Reviewed-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: Anirudh Rayabharam mail@anirudhrb.com Link: https://lore.kernel.org/r/20210820190122.16379-2-mail@anirudhrb.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/usbip/vhci_hcd.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c index 98636fbf7188..46a46cde2070 100644 --- a/drivers/usb/usbip/vhci_hcd.c +++ b/drivers/usb/usbip/vhci_hcd.c @@ -952,8 +952,32 @@ static void vhci_device_unlink_cleanup(struct vhci_device *vdev) spin_lock(&vdev->priv_lock);
list_for_each_entry_safe(unlink, tmp, &vdev->unlink_tx, list) { + struct urb *urb; + + /* give back urb of unsent unlink request */ pr_info("unlink cleanup tx %lu\n", unlink->unlink_seqnum); + + urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum); + if (!urb) { + list_del(&unlink->list); + kfree(unlink); + continue; + } + + urb->status = -ENODEV; + + usb_hcd_unlink_urb_from_ep(hcd, urb); + list_del(&unlink->list); + + spin_unlock(&vdev->priv_lock); + spin_unlock_irqrestore(&vhci->lock, flags); + + usb_hcd_giveback_urb(hcd, urb, urb->status); + + spin_lock_irqsave(&vhci->lock, flags); + spin_lock(&vdev->priv_lock); + kfree(unlink); }