From 8eb58994dd96da7055721c68e46b732febe671ae Mon Sep 17 00:00:00 2001 From: Nicolas Saenz Julienne Date: Tue, 8 Jan 2019 16:45:22 +0100 Subject: [PATCH] usb: hub: add retry routine after intr URB submit error The hub sends hot-plug events to the host trough it's interrupt URB. The driver takes care of completing the URB and re-submitting it. Completion errors are handled in the hub_event() work, yet submission errors are ignored, rendering the device unresponsive. All further events are lost. It is fairly hard to find this issue in the wild, since you have to time the USB hot-plug event with the URB submission failure. For instance it could be the system running out of memory or some malfunction in the USB controller driver. Nevertheless, it's pretty reasonable to think it'll happen sometime. One can trigger this issue using eBPF's function override feature (see BCC's inject.py script). This patch adds a retry routine to the event of a submission error. The HUB driver will try to re-submit the URB once every second until it's successful or the HUB is disconnected. As some USB subsystems already take care of this issue, the implementation was inspired from usbhid/hid_core.c's. Signed-off-by: Nicolas Saenz Julienne Reviewed-by: Oliver Neukum Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 43 ++++++++++++++++++++++++++++++++++++------ drivers/usb/core/hub.h | 2 ++ 2 files changed, 39 insertions(+), 6 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 1d1e61e980f3..713ab85332f8 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -607,6 +607,36 @@ static int hub_port_status(struct usb_hub *hub, int port1, status, change, NULL); } +static void hub_resubmit_irq_urb(struct usb_hub *hub) +{ + unsigned long flags; + int status; + + spin_lock_irqsave(&hub->irq_urb_lock, flags); + + if (hub->quiescing) { + spin_unlock_irqrestore(&hub->irq_urb_lock, flags); + return; + } + + status = usb_submit_urb(hub->urb, GFP_ATOMIC); + if (status && status != -ENODEV && status != -EPERM && + status != -ESHUTDOWN) { + dev_err(hub->intfdev, "resubmit --> %d\n", status); + mod_timer(&hub->irq_urb_retry, jiffies + HZ); + } + + spin_unlock_irqrestore(&hub->irq_urb_lock, flags); +} + +static void hub_retry_irq_urb(struct timer_list *t) +{ + struct usb_hub *hub = from_timer(hub, t, irq_urb_retry); + + hub_resubmit_irq_urb(hub); +} + + static void kick_hub_wq(struct usb_hub *hub) { struct usb_interface *intf; @@ -709,12 +739,7 @@ static void hub_irq(struct urb *urb) kick_hub_wq(hub); resubmit: - if (hub->quiescing) - return; - - status = usb_submit_urb(hub->urb, GFP_ATOMIC); - if (status != 0 && status != -ENODEV && status != -EPERM) - dev_err(hub->intfdev, "resubmit --> %d\n", status); + hub_resubmit_irq_urb(hub); } /* USB 2.0 spec Section 11.24.2.3 */ @@ -1264,10 +1289,13 @@ enum hub_quiescing_type { static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type) { struct usb_device *hdev = hub->hdev; + unsigned long flags; int i; /* hub_wq and related activity won't re-trigger */ + spin_lock_irqsave(&hub->irq_urb_lock, flags); hub->quiescing = 1; + spin_unlock_irqrestore(&hub->irq_urb_lock, flags); if (type != HUB_SUSPEND) { /* Disconnect all the children */ @@ -1278,6 +1306,7 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type) } /* Stop hub_wq and related activity */ + del_timer_sync(&hub->irq_urb_retry); usb_kill_urb(hub->urb); if (hub->has_indicators) cancel_delayed_work_sync(&hub->leds); @@ -1810,6 +1839,8 @@ static int hub_probe(struct usb_interface *intf, const struct usb_device_id *id) INIT_DELAYED_WORK(&hub->leds, led_work); INIT_DELAYED_WORK(&hub->init_work, NULL); INIT_WORK(&hub->events, hub_event); + spin_lock_init(&hub->irq_urb_lock); + timer_setup(&hub->irq_urb_retry, hub_retry_irq_urb, 0); usb_get_intf(intf); usb_get_dev(hdev); diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 4accfb63f7dc..a9e24e4b8df1 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -69,6 +69,8 @@ struct usb_hub { struct delayed_work leds; struct delayed_work init_work; struct work_struct events; + spinlock_t irq_urb_lock; + struct timer_list irq_urb_retry; struct usb_port **ports; };