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

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commit 18abf87436 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 b1de23dbec
commit cdaae487e8
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 */ /* the order here is essential */
usb_kill_urb(desc->command); usb_poison_urb(desc->command);
usb_kill_urb(desc->validity); usb_poison_urb(desc->validity);
usb_kill_urb(desc->response); 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) 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 (!desc->count) {
if (!test_bit(WDM_DISCONNECTING, &desc->flags)) { if (!test_bit(WDM_DISCONNECTING, &desc->flags)) {
dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n"); dev_dbg(&desc->intf->dev, "wdm_release: cleanup\n");
kill_urbs(desc); poison_urbs(desc);
spin_lock_irq(&desc->iuspin); spin_lock_irq(&desc->iuspin);
desc->resp_count = 0; desc->resp_count = 0;
spin_unlock_irq(&desc->iuspin); spin_unlock_irq(&desc->iuspin);
desc->manage_power(desc->intf, 0); desc->manage_power(desc->intf, 0);
unpoison_urbs(desc);
} else { } else {
/* must avoid dev_printk here as desc->intf is invalid */ /* must avoid dev_printk here as desc->intf is invalid */
pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__); pr_debug(KBUILD_MODNAME " %s: device gone - cleaning up\n", __func__);
@ -1036,9 +1048,9 @@ static void wdm_disconnect(struct usb_interface *intf)
wake_up_all(&desc->wait); wake_up_all(&desc->wait);
mutex_lock(&desc->rlock); mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock); mutex_lock(&desc->wlock);
poison_urbs(desc);
cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr); cancel_work_sync(&desc->service_outs_intr);
kill_urbs(desc);
mutex_unlock(&desc->wlock); mutex_unlock(&desc->wlock);
mutex_unlock(&desc->rlock); mutex_unlock(&desc->rlock);
@ -1079,9 +1091,10 @@ static int wdm_suspend(struct usb_interface *intf, pm_message_t message)
set_bit(WDM_SUSPENDING, &desc->flags); set_bit(WDM_SUSPENDING, &desc->flags);
spin_unlock_irq(&desc->iuspin); spin_unlock_irq(&desc->iuspin);
/* callback submits work - order is essential */ /* callback submits work - order is essential */
kill_urbs(desc); poison_urbs(desc);
cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr); cancel_work_sync(&desc->service_outs_intr);
unpoison_urbs(desc);
} }
if (!PMSG_IS_AUTO(message)) { if (!PMSG_IS_AUTO(message)) {
mutex_unlock(&desc->wlock); mutex_unlock(&desc->wlock);
@ -1139,7 +1152,7 @@ static int wdm_pre_reset(struct usb_interface *intf)
wake_up_all(&desc->wait); wake_up_all(&desc->wait);
mutex_lock(&desc->rlock); mutex_lock(&desc->rlock);
mutex_lock(&desc->wlock); mutex_lock(&desc->wlock);
kill_urbs(desc); poison_urbs(desc);
cancel_work_sync(&desc->rxwork); cancel_work_sync(&desc->rxwork);
cancel_work_sync(&desc->service_outs_intr); cancel_work_sync(&desc->service_outs_intr);
return 0; return 0;
@ -1150,6 +1163,7 @@ static int wdm_post_reset(struct usb_interface *intf)
struct wdm_device *desc = wdm_find_device(intf); struct wdm_device *desc = wdm_find_device(intf);
int rv; int rv;
unpoison_urbs(desc);
clear_bit(WDM_OVERFLOW, &desc->flags); clear_bit(WDM_OVERFLOW, &desc->flags);
clear_bit(WDM_RESETTING, &desc->flags); clear_bit(WDM_RESETTING, &desc->flags);
rv = recover_from_urb_loss(desc); rv = recover_from_urb_loss(desc);