patch "USB: CDC-ACM: fix poison/unpoison imbalance" added to usb-next

This is a note to let you know that I've just added the patch titled

USB: CDC-ACM: fix poison/unpoison imbalance

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release during the merge window.

If you have any questions about this process, please let me know.

From a8b3b519618f30a87a304c4e120267ce6f8dc68a Mon Sep 17 00:00:00 2001
From: Oliver Neukum <[email protected]>
Date: Wed, 21 Apr 2021 09:45:13 +0200
Subject: 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.

---
 drivers/usb/class/cdc-acm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

index b74713518b3a..c103961c3fae 100644
@@ -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);
 

2.31.1