cdc-acm: close race betrween suspend() and acm_softint
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>
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				| @ -557,14 +557,14 @@ 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); | ||||
| 		} | ||||
| 		clear_bit(EVENT_RX_STALL, &acm->flags); | ||||
| 	} | ||||
| 
 | ||||
| 	if (test_and_clear_bit(EVENT_TTY_WAKEUP, &acm->flags)) | ||||
|  | ||||
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