From acb072863888c916b539271c9a2c2e91fbfcceb6 Mon Sep 17 00:00:00 2001 From: Ray Chi Date: Mon, 7 Nov 2022 15:27:54 +0800 Subject: [PATCH] UPSTREAM: usb: core: stop USB enumeration if too many retries When a broken USB accessory connects to a USB host, usbcore might keep doing enumeration retries. If the host has a watchdog mechanism, the kernel panic will happen on the host. This patch provides an attribute early_stop to limit the numbers of retries for each port of a hub. If a port was marked with early_stop attribute, unsuccessful connection attempts will fail quickly. In addition, if an early_stop port has failed to initialize, it will ignore all future connection events until early_stop attribute is clear. Signed-off-by: Ray Chi Reviewed-by: Alan Stern Link: https://lore.kernel.org/r/20221107072754.3336357-1-raychi@google.com Signed-off-by: Greg Kroah-Hartman Bug: 282876796 Change-Id: I48eff1dbbc341ef893c8abc20953b7e9a62244da (cherry picked from commit 430d57f53eb1cdbf9ba9bbd397317912b3cd2de5) Signed-off-by: Ray Chi (cherry picked from commit 278999b347af30f37e67314d7a198478b89be2dc) --- Documentation/ABI/testing/sysfs-bus-usb | 11 +++++ drivers/usb/core/hub.c | 60 +++++++++++++++++++++++++ drivers/usb/core/hub.h | 4 ++ drivers/usb/core/port.c | 27 +++++++++++ 4 files changed, 102 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index d71ce6cc1c7c..b93c5ad0cccd 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -264,6 +264,17 @@ Description: attached to the port will not be detected, initialized, or enumerated. +What: /sys/bus/usb/devices/...//port/early_stop +Date: Sep 2022 +Contact: Ray Chi +Description: + Some USB hosts have some watchdog mechanisms so that the device + may enter ramdump if it takes a long time during port initialization. + This attribute allows each port just has two attempts so that the + port initialization will be failed quickly. In addition, if a port + which is marked with early_stop has failed to initialize, it will ignore + all future connections until this attribute is clear. + What: /sys/bus/usb/devices/...//port/state Date: June 2023 Contact: Roy Luo diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 58e7d1e4430f..a739403a9e45 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -3098,6 +3098,48 @@ done: return status; } +/* + * hub_port_stop_enumerate - stop USB enumeration or ignore port events + * @hub: target hub + * @port1: port num of the port + * @retries: port retries number of hub_port_init() + * + * Return: + * true: ignore port actions/events or give up connection attempts. + * false: keep original behavior. + * + * This function will be based on retries to check whether the port which is + * marked with early_stop attribute would stop enumeration or ignore events. + * + * Note: + * This function didn't change anything if early_stop is not set, and it will + * prevent all connection attempts when early_stop is set and the attempts of + * the port are more than 1. + */ +static bool hub_port_stop_enumerate(struct usb_hub *hub, int port1, int retries) +{ + struct usb_port *port_dev = hub->ports[port1 - 1]; + + if (port_dev->early_stop) { + if (port_dev->ignore_event) + return true; + + /* + * We want unsuccessful attempts to fail quickly. + * Since some devices may need one failure during + * port initialization, we allow two tries but no + * more. + */ + if (retries < 2) + return false; + + port_dev->ignore_event = 1; + } else + port_dev->ignore_event = 0; + + return port_dev->ignore_event; +} + /* Check if a port is power on */ int usb_port_is_power_on(struct usb_hub *hub, unsigned int portstatus) { @@ -4813,6 +4855,11 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, do_new_scheme = use_new_scheme(udev, retry_counter, port_dev); for (retries = 0; retries < GET_DESCRIPTOR_TRIES; (++retries, msleep(100))) { + if (hub_port_stop_enumerate(hub, port1, retries)) { + retval = -ENODEV; + break; + } + if (do_new_scheme) { struct usb_device_descriptor *buf; int r = 0; @@ -5263,6 +5310,11 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, status = 0; for (i = 0; i < PORT_INIT_TRIES; i++) { + if (hub_port_stop_enumerate(hub, port1, i)) { + status = -ENODEV; + break; + } + usb_lock_port(port_dev); mutex_lock(hcd->address0_mutex); retry_locked = true; @@ -5631,6 +5683,10 @@ static void port_event(struct usb_hub *hub, int port1) if (!pm_runtime_active(&port_dev->dev)) return; + /* skip port actions if ignore_event and early_stop are true */ + if (port_dev->ignore_event && port_dev->early_stop) + return; + if (hub_handle_remote_wakeup(hub, port1, portstatus, portchange)) connect_change = 1; @@ -5954,6 +6010,10 @@ static int usb_reset_and_verify_device(struct usb_device *udev) mutex_lock(hcd->address0_mutex); for (i = 0; i < PORT_INIT_TRIES; ++i) { + if (hub_port_stop_enumerate(parent_hub, port1, i)) { + ret = -ENODEV; + break; + } /* ep0 maxpacket size may change; let the HCD know about it. * Other endpoints will be handled by re-enumeration. */ diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index f244cc475e3e..37897afd1b64 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -92,6 +92,8 @@ struct usb_hub { * @is_superspeed cache super-speed status * @usb3_lpm_u1_permit: whether USB3 U1 LPM is permitted. * @usb3_lpm_u2_permit: whether USB3 U2 LPM is permitted. + * @early_stop: whether port initialization will be stopped earlier. + * @ignore_event: whether events of the port are ignored. */ struct usb_port { struct usb_device *child; @@ -107,6 +109,8 @@ struct usb_port { u32 over_current_count; u8 portnum; u32 quirks; + unsigned int early_stop:1; + unsigned int ignore_event:1; unsigned int is_superspeed:1; unsigned int usb3_lpm_u1_permit:1; unsigned int usb3_lpm_u2_permit:1; diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c index e458ed17c7a1..b2cad06885b5 100644 --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -17,6 +17,32 @@ static int usb_port_block_power_off; static const struct attribute_group *port_dev_group[]; +static ssize_t early_stop_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct usb_port *port_dev = to_usb_port(dev); + + return sysfs_emit(buf, "%s\n", port_dev->early_stop ? "yes" : "no"); +} + +static ssize_t early_stop_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct usb_port *port_dev = to_usb_port(dev); + bool value; + + if (kstrtobool(buf, &value)) + return -EINVAL; + + if (value) + port_dev->early_stop = 1; + else + port_dev->early_stop = 0; + + return count; +} +static DEVICE_ATTR_RW(early_stop); + static ssize_t disable_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -247,6 +273,7 @@ static struct attribute *port_dev_attrs[] = { &dev_attr_quirks.attr, &dev_attr_over_current_count.attr, &dev_attr_disable.attr, + &dev_attr_early_stop.attr, NULL, };