[PATCH 3/4] igorplugusb: break cyclical race on disconnect

Oliver Neukum
2022-05-12T12:39:03Z

The driver uses a timer, that may submit the URB and
the URB may start the timer. No simple order of killing
can break te cycle. Poison the URB before killing
the timer.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
drivers/media/rc/igorplugusb.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/media/rc/igorplugusb.c b/drivers/media/rc/igorplugusb.c
index 1afba95409ff..b2245849f7aa 100644
--- a/drivers/media/rc/igorplugusb.c
+++ b/drivers/media/rc/igorplugusb.c
@@ -126,7 +126,7 @@ static void igorplugusb_cmd(struct igorplugusb *ir, int cmd)
ir->request.bRequest = cmd;
ir->urb->transfer_flags = 0;
ret = usb_submit_urb(ir->urb, GFP_ATOMIC);
- if (ret)
+ if (ret && ret != -EPERM)
dev_err(ir->dev, "submit urb failed: %d", ret);
}

@@ -223,7 +223,9 @@ static int igorplugusb_probe(struct usb_interface *intf,

return 0;
fail:
+ usb_poison_urb(ir->urb);
del_timer(&ir->timer);
+ usb_unpoison_urb(ir->urb);
usb_free_urb(ir->urb);
rc_free_device(ir->rc);
kfree(ir->buf_in);
@@ -236,9 +238,10 @@ static void igorplugusb_disconnect(struct usb_interface *intf)
struct igorplugusb *ir = usb_get_intfdata(intf);

rc_unregister_device(ir->rc);
+ usb_poison_urb(ir->urb);
del_timer_sync(&ir->timer);
usb_set_intfdata(intf, NULL);
- usb_kill_urb(ir->urb);
+ usb_unpoison_urb(ir->urb);
usb_free_urb(ir->urb);
kfree(ir->buf_in);
}
--
2.35.3