On Thu, 18 Apr 2019, Alan Stern wrote:
> On Wed, 17 Apr 2019, Alan Stern wrote:
>
> > I'm still having trouble understanding this. Here's some more
> > debugging.
>
> Let's try this again. The patch format was wrong.
One more try, this time with the syz command line.
Incidentally, the console log from the last test had a very troubling
entry showing the runtime PM usage counter for the hub interface was
set to -4! Whatever caused the counter to go negative is probably also
the reason for this bug.
Alan Stern
#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git e12e00e388de
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1016,6 +1016,9 @@ static void hub_activate(struct usb_hub
bool need_debounce_delay = false;
unsigned delay;
+ dev_info(hub->intfdev, "%p %s type %d discon %d\n",
+ hub, __func__, type, hub->disconnected);
+
/* Continue a partial initialization */
if (type == HUB_INIT2 || type == HUB_INIT3) {
device_lock(&hdev->dev);
@@ -1299,6 +1302,8 @@ static void hub_quiesce(struct usb_hub *
unsigned long flags;
int i;
+ dev_info(hub->intfdev, "%p %s type %d\n", hub, __func__, type);
+
/* hub_wq and related activity won't re-trigger */
spin_lock_irqsave(&hub->irq_urb_lock, flags);
hub->quiescing = 1;
@@ -3711,7 +3716,9 @@ static int hub_suspend(struct usb_interf
}
}
- dev_dbg(&intf->dev, "%s\n", __func__);
+ dev_info(&intf->dev, "%p %s usage %d\n",
+ hub, __func__,
+ atomic_read(&intf->dev.power.usage_count));
/* stop hub_wq and related activity */
hub_quiesce(hub, HUB_SUSPEND);
@@ -3756,7 +3763,7 @@ static int hub_resume(struct usb_interfa
{
struct usb_hub *hub = usb_get_intfdata(intf);
- dev_dbg(&intf->dev, "%s\n", __func__);
+ dev_info(&intf->dev, "%p %s\n", hub, __func__);
hub_activate(hub, HUB_RESUME);
/*
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -358,7 +358,11 @@ static int usb_probe_interface(struct de
intf->needs_altsetting0 = 0;
}
+ dev_info(dev, "pre-probe usage %d\n",
+ atomic_read(&intf->dev.power.usage_count));
error = driver->probe(intf, id);
+ dev_info(dev, "post-probe usage %d\n",
+ atomic_read(&intf->dev.power.usage_count));
if (error)
goto err;
@@ -420,7 +424,11 @@ static int usb_unbind_interface(struct d
if (!driver->soft_unbind || udev->state == USB_STATE_NOTATTACHED)
usb_disable_interface(udev, intf, false);
+ dev_info(dev, "pre-discon usage %d\n",
+ atomic_read(&intf->dev.power.usage_count));
driver->disconnect(intf);
+ dev_info(dev, "post-discon usage %d\n",
+ atomic_read(&intf->dev.power.usage_count));
/* Free streams */
for (i = 0, j = 0; i < intf->cur_altsetting->desc.bNumEndpoints; i++) {
