summaryrefslogtreecommitdiffstats
path: root/drivers/usb/core/hub.c
diff options
context:
space:
mode:
authorRay Chi <raychi@google.com>2022-11-07 15:27:54 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-11-08 16:50:21 +0100
commit430d57f53eb1cdbf9ba9bbd397317912b3cd2de5 (patch)
treed099fea6ebe65a15b293b203ee8461c4ab6bbeec /drivers/usb/core/hub.c
parent04914233561377fc0369b984c9d19ec1b6ce2845 (diff)
downloadlinux-stable-430d57f53eb1cdbf9ba9bbd397317912b3cd2de5.tar.gz
linux-stable-430d57f53eb1cdbf9ba9bbd397317912b3cd2de5.tar.bz2
linux-stable-430d57f53eb1cdbf9ba9bbd397317912b3cd2de5.zip
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 <raychi@google.com> Reviewed-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20221107072754.3336357-1-raychi@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core/hub.c')
-rw-r--r--drivers/usb/core/hub.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index bbab424b0d55..77e73fc8d673 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3081,6 +3081,48 @@ 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)
{
@@ -4796,6 +4838,11 @@ 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;
@@ -5246,6 +5293,11 @@ 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;
@@ -5614,6 +5666,10 @@ 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;
@@ -5927,6 +5983,10 @@ 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. */