Commit 681c2486 authored Apr 15, 2020 by Oliver Neukum Committed by Greg Kroah-Hartman Apr 29, 2020

cdc-acm: close race betrween suspend() and acm_softint



commit 0afccd7601514c4b83d8cc58c740089cc447051d upstream.

Suspend increments a counter, then kills the URBs,
then kills the scheduled work. The scheduled work, however,
may reschedule the URBs. Fix this by having the work
check the counter.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: Jonas Karlsson <jonas.karlsson@actia.se>
Link: https://lore.kernel.org/r/20200415151358.32664-1-oneukum@suse.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 90fbd077

drivers/usb/class/cdc-acm.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -563,15 +563,15 @@ static void acm_softint(struct work_struct *work)
		struct acm *acm = container_of(work, struct acm, work);

		if (test_bit(EVENT_RX_STALL, &acm->flags)) {
		if (!(usb_autopm_get_interface(acm->data))) {
		smp_mb(); /* against acm_suspend() */
		if (!acm->susp_count) {
		for (i = 0; i < acm->rx_buflimit; i++)
		usb_kill_urb(acm->read_urbs[i]);
		usb_clear_halt(acm->dev, acm->in);
		acm_submit_read_urbs(acm, GFP_KERNEL);
		usb_autopm_put_interface(acm->data);
		}
		clear_bit(EVENT_RX_STALL, &acm->flags);
		}
		}

		if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags))
		tty_port_tty_wakeup(&acm->port);