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cdc-wdm: untangle a circular dependency between callback and softint

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commit 18abf874367456540846319574864e6ff32752e2 upstream.

We have a cycle of callbacks scheduling works which submit
URBs with those callbacks. This needs to be blocked, stopped
and unblocked to untangle the circle.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20210426092622.20433-1-oneukum@suse.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oliver Neukum 2021-04-26 11:26:22 +02:00 committed by Greg Kroah-Hartman
parent 12d16c24f3
commit 652c9689f5
1 changed files with 22 additions and 8 deletions
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30
drivers/usb/class/cdc-wdm.c
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@ -321,12 +321,23 @@ exit:
}
static void kill_urbs(struct wdm_device *desc)
static void poison_urbs(struct wdm_device *desc)
{
/* the order here is essential */
usb_kill_urb(desc->command);
usb_kill_urb(desc->validity);
usb_kill_urb(desc->response);
usb_poison_urb(desc->command);
usb_poison_urb(desc->validity);
usb_poison_urb(desc->response);
}
static void unpoison_urbs(struct wdm_device *desc)
{
/*
* the order here is not essential
* it is symmetrical just to be nice
*/
usb_unpoison_urb(desc->response);
usb_unpoison_urb(desc->validity);
usb_unpoison_urb(desc->command);
}
static void free_urbs(struct wdm_device *desc)
@ -741,11 +752,12 @@ static int wdm_release(struct inode *inode, struct file *file)
if (!desc->count) {
if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
kill_urbs(desc);
poison_urbs(desc);
spin_lock_irq(&desc->iuspin);
desc->resp_count = 0;
spin_unlock_irq(&desc->iuspin);
desc->manage_power(desc->intf, 0);
unpoison_urbs(desc);
} else {
/* must avoid dev_printk here as desc->intf is invalid */
pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
@ -1037,9 +1049,9 @@ static void wdm_disconnect(struct usb_interface *intf)
wake_up_all(&desc->wait);
mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock);
poison_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
kill_urbs(desc);
mutex_unlock(&desc->wlock);
mutex_unlock(&desc->rlock);
@ -1080,9 +1092,10 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
set_bit(WDM_SUSPENDING, &desc->flags);
spin_unlock_irq(&desc->iuspin);
/* callback submits work - order is essential */
kill_urbs(desc);
poison_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
unpoison_urbs(desc);
}
if (!PMSG_IS_AUTO(message)) {
mutex_unlock(&desc->wlock);
@ -1140,7 +1153,7 @@ static int wdm_pre_reset(struct usb_interface *intf)
wake_up_all(&desc->wait);
mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock);
kill_urbs(desc);
poison_urbs(desc);
cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr);
return 0;
@ -1151,6 +1164,7 @@ static int wdm_post_reset(struct usb_interface *intf)
struct wdm_device *desc = wdm_find_device(intf);
int rv;
unpoison_urbs(desc);
clear_bit(WDM_OVERFLOW, &desc->flags);
clear_bit(WDM_RESETTING, &desc->flags);
rv = recover_from_urb_loss(desc);