From a8b3b519618f30a87a304c4e120267ce6f8dc68a Mon Sep 17 00:00:00 2001 From: Oliver Neukum Date: Wed, 21 Apr 2021 09:45:13 +0200 Subject: [PATCH] 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: 6069e3e927c8f ("USB: cdc-acm: untangle a circular dependency between callback and softint") Signed-off-by: Oliver Neukum Cc: stable Link: https://lore.kernel.org/r/20210421074513.4327-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index b747135..c103961 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -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); -- 2.7.4