Commit a8b3b519 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
Browse files

USB: CDC-ACM: fix poison/unpoison imbalance 



suspend() does its poisoning conditionally, resume() does it
unconditionally. On a device with combined interfaces this
will balance, on a device with two interfaces the counter will
go negative and resubmission will fail.

Both actions need to be done conditionally.

Fixes: 6069e3e9 ("USB: cdc-acm: untangle a circular dependency between callback and softint")
Signed-off-by: default avatarOliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210421074513.4327-1-oneukum@suse.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ca91fd8c

drivers/usb/class/cdc-acm.c

+2 −1
Original line number Diff line number Diff line
@@ -1624,12 +1624,13 @@ static int acm_resume(struct usb_interface *intf) 
	struct urb *urb;

	int rv = 0;



	acm_unpoison_urbs(acm);

	spin_lock_irq(&acm->write_lock);



	if (--acm->susp_count)

		goto out;



	acm_unpoison_urbs(acm);



	if (tty_port_initialized(&acm->port)) {

		rv = usb_submit_urb(acm->ctrlurb, GFP_ATOMIC);