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usb/hcd: Send a uevent signaling that the host controller had died

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This change will send an OFFLINE event to udev with the ERROR=DEAD
environment variable set when the HC dies.

By notifying user space the appropriate policies can be applied.
i.e.,
 * Collect error logs.
 * Notify the user that USB is no longer functional.
 * Perform a graceful reboot.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Raul E Rangel 2019-04-19 09:30:22 -06:00 committed by Greg Kroah-Hartman
parent cf28369c63
commit a4d6a2989d
3 changed files with 52 additions and 0 deletions
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27
Documentation/ABI/testing/usb-uevent Normal file
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@ -0,0 +1,27 @@
What: Raise a uevent when a USB Host Controller has died
Date: 2019-04-17
KernelVersion: 5.2
Contact: linux-usb@vger.kernel.org
Description: When the USB Host Controller has entered a state where it is no
longer functional a uevent will be raised. The uevent will
contain ACTION=offline and ERROR=DEAD.
Here is an example taken using udevadm monitor -p:
KERNEL[130.428945] offline /devices/pci0000:00/0000:00:10.0/usb2 (usb)
ACTION=offline
BUSNUM=002
DEVNAME=/dev/bus/usb/002/001
DEVNUM=001
DEVPATH=/devices/pci0000:00/0000:00:10.0/usb2
DEVTYPE=usb_device
DRIVER=usb
ERROR=DEAD
MAJOR=189
MINOR=128
PRODUCT=1d6b/2/414
SEQNUM=2168
SUBSYSTEM=usb
TYPE=9/0/1
Users: chromium-os-dev@chromium.org

24
drivers/usb/core/hcd.c
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@ -2435,6 +2435,19 @@ EXPORT_SYMBOL_GPL(usb_hcd_irq);
/*-------------------------------------------------------------------------*/ /*-------------------------------------------------------------------------*/
/* Workqueue routine for when the root-hub has died. */
static void hcd_died_work(struct work_struct *work)
{
struct usb_hcd *hcd = container_of(work, struct usb_hcd, died_work);
static char *env[] = {
"ERROR=DEAD",
NULL
};
/* Notify user space that the host controller has died */
kobject_uevent_env(&hcd->self.root_hub->dev.kobj, KOBJ_OFFLINE, env);
}
/** /**
* usb_hc_died - report abnormal shutdown of a host controller (bus glue) * usb_hc_died - report abnormal shutdown of a host controller (bus glue)
* @hcd: pointer to the HCD representing the controller * @hcd: pointer to the HCD representing the controller
@ -2475,6 +2488,13 @@ void usb_hc_died (struct usb_hcd *hcd)
usb_kick_hub_wq(hcd->self.root_hub); usb_kick_hub_wq(hcd->self.root_hub);
} }
} }
/* Handle the case where this function gets called with a shared HCD */
if (usb_hcd_is_primary_hcd(hcd))
schedule_work(&hcd->died_work);
else
schedule_work(&hcd->primary_hcd->died_work);
spin_unlock_irqrestore (&hcd_root_hub_lock, flags); spin_unlock_irqrestore (&hcd_root_hub_lock, flags);
/* Make sure that the other roothub is also deallocated. */ /* Make sure that the other roothub is also deallocated. */
} }
@ -2542,6 +2562,8 @@ struct usb_hcd *__usb_create_hcd(const struct hc_driver *driver,
INIT_WORK(&hcd->wakeup_work, hcd_resume_work); INIT_WORK(&hcd->wakeup_work, hcd_resume_work);
#endif #endif
INIT_WORK(&hcd->died_work, hcd_died_work);
hcd->driver = driver; hcd->driver = driver;
hcd->speed = driver->flags & HCD_MASK; hcd->speed = driver->flags & HCD_MASK;
hcd->product_desc = (driver->product_desc) ? driver->product_desc : hcd->product_desc = (driver->product_desc) ? driver->product_desc :
@ -2895,6 +2917,7 @@ int usb_add_hcd(struct usb_hcd *hcd,
#ifdef CONFIG_PM #ifdef CONFIG_PM
cancel_work_sync(&hcd->wakeup_work); cancel_work_sync(&hcd->wakeup_work);
#endif #endif
cancel_work_sync(&hcd->died_work);
mutex_lock(&usb_bus_idr_lock); mutex_lock(&usb_bus_idr_lock);
usb_disconnect(&rhdev); /* Sets rhdev to NULL */ usb_disconnect(&rhdev); /* Sets rhdev to NULL */
mutex_unlock(&usb_bus_idr_lock); mutex_unlock(&usb_bus_idr_lock);
@ -2955,6 +2978,7 @@ void usb_remove_hcd(struct usb_hcd *hcd)
#ifdef CONFIG_PM #ifdef CONFIG_PM
cancel_work_sync(&hcd->wakeup_work); cancel_work_sync(&hcd->wakeup_work);
#endif #endif
cancel_work_sync(&hcd->died_work);
mutex_lock(&usb_bus_idr_lock); mutex_lock(&usb_bus_idr_lock);
usb_disconnect(&rhdev); /* Sets rhdev to NULL */ usb_disconnect(&rhdev); /* Sets rhdev to NULL */

1
include/linux/usb/hcd.h
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@ -98,6 +98,7 @@ struct usb_hcd {
#ifdef CONFIG_PM #ifdef CONFIG_PM
struct work_struct wakeup_work; /* for remote wakeup */ struct work_struct wakeup_work; /* for remote wakeup */
#endif #endif
struct work_struct died_work; /* for when the device dies */
/* /*
* hardware info/state * hardware info/state