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authorOliver Neukum <oneukum@suse.com>2021-04-26 11:26:22 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-05-19 10:08:31 +0200
commitcdaae487e85b60c4ba273a40a260b1af49341119 (patch)
tree1db8a924752a03faded4ce37db0b9a4e42c06b50
parentb1de23dbeca7d6f8c5df66512e0aa7c7d9e18b7e (diff)
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cdc-wdm: untangle a circular dependency between callback and softint
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>
-rw-r--r--drivers/usb/class/cdc-wdm.c30
1 files changed, 22 insertions, 8 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index fc1a219ad0a7..de7bb8e6a1ef 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -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__);
@@ -1036,9 +1048,9 @@ 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);
@@ -1079,9 +1091,10 @@ 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);
@@ -1139,7 +1152,7 @@ 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;
@@ -1150,6 +1163,7 @@ 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);