usb_udc_connect_control does not check to see if the udc has already been started. This causes gadget->ops->pullup to be called through usb_gadget_connect when invoked from usb_udc_vbus_handler even before usb_gadget_udc_start is called. Guard this by checking for udc->started in usb_udc_connect_control before invoking usb_gadget_connect.

Guarding udc->vbus, udc->started, gadget->connect, gadget->deactivate related functions with connect_lock. usb_gadget_connect_locked, usb_gadget_disconnect_locked, usb_udc_connect_control_locked, usb_gadget_udc_start_locked, usb_gadget_udc_stop_locked are called with this lock held as they can be simulataneously invoked from different code paths.

Adding an additional check to make sure udc is started(udc->started) before pullup callback is invoked.

Cc: stable@vger.kernel.org Fixes: 628ef0d273a6 ("usb: udc: add usb_udc_vbus_handler") Signed-off-by: Badhri Jagan Sridharan badhri@google.com --- * Fixed commit message comments. * Renamed udc_connect_control_lock to connect_lock and made it per device. * udc->vbus, udc->started, gadget->connect, gadget->deactivate are all now guarded by connect_lock. * Code now checks for udc->started to be set before invoking pullup callback. --- drivers/usb/gadget/udc/core.c | 140 +++++++++++++++++++++++----------- 1 file changed, 96 insertions(+), 44 deletions(-)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index 3dcbba739db6..41d3a1998cff 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -37,6 +37,10 @@ static struct bus_type gadget_bus_type; * @vbus: for udcs who care about vbus status, this value is real vbus status; * for udcs who do not care about vbus status, this value is always true * @started: the UDC's started state. True if the UDC had started. + * @connect_lock: protects udc->vbus, udc->started, gadget->connect, gadget->deactivate related + * functions. usb_gadget_connect_locked, usb_gadget_disconnect_locked, + * usb_udc_connect_control_locked, usb_gadget_udc_start_locked, usb_gadget_udc_stop_locked are + * called with this lock held. * * This represents the internal data structure which is used by the UDC-class * to hold information about udc driver and gadget together. @@ -48,6 +52,7 @@ struct usb_udc { struct list_head list; bool vbus; bool started; + struct mutex connect_lock; };

static struct class *udc_class; @@ -687,17 +692,8 @@ int usb_gadget_vbus_disconnect(struct usb_gadget *gadget) } EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect);

-/** - * usb_gadget_connect - software-controlled connect to USB host - * @gadget:the peripheral being connected - * - * Enables the D+ (or potentially D-) pullup. The host will start - * enumerating this gadget when the pullup is active and a VBUS session - * is active (the link is powered). - * - * Returns zero on success, else negative errno. - */ -int usb_gadget_connect(struct usb_gadget *gadget) +/* Internal version of usb_gadget_connect needs to be called with udc_connect_control_lock held. */ +int usb_gadget_connect_locked(struct usb_gadget *gadget) { int ret = 0;

@@ -706,10 +702,12 @@ int usb_gadget_connect(struct usb_gadget *gadget) goto out; }

- if (gadget->deactivated) { + if (gadget->deactivated || !gadget->udc->started) { /* * If gadget is deactivated we only save new state. * Gadget will be connected automatically after activation. + * + * udc first needs to be started before gadget can be pulled up. */ gadget->connected = true; goto out; @@ -724,22 +722,31 @@ int usb_gadget_connect(struct usb_gadget *gadget)

return ret; } -EXPORT_SYMBOL_GPL(usb_gadget_connect);

/** - * usb_gadget_disconnect - software-controlled disconnect from USB host - * @gadget:the peripheral being disconnected - * - * Disables the D+ (or potentially D-) pullup, which the host may see - * as a disconnect (when a VBUS session is active). Not all systems - * support software pullup controls. + * usb_gadget_connect - software-controlled connect to USB host + * @gadget:the peripheral being connected * - * Following a successful disconnect, invoke the ->disconnect() callback - * for the current gadget driver so that UDC drivers don't need to. + * Enables the D+ (or potentially D-) pullup. The host will start + * enumerating this gadget when the pullup is active and a VBUS session + * is active (the link is powered). * * Returns zero on success, else negative errno. */ -int usb_gadget_disconnect(struct usb_gadget *gadget) +int usb_gadget_connect(struct usb_gadget *gadget) +{ + int ret; + + mutex_lock(&gadget->udc->connect_lock); + ret = usb_gadget_connect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(usb_gadget_connect); + +/* Internal version of usb_gadget_disconnect needs to be called with udc->connect_lock held. */ +int usb_gadget_disconnect_locked(struct usb_gadget *gadget) { int ret = 0;

@@ -751,10 +758,12 @@ int usb_gadget_disconnect(struct usb_gadget *gadget) if (!gadget->connected) goto out;

- if (gadget->deactivated) { + if (gadget->deactivated || !gadget->udc->started) { /* * If gadget is deactivated we only save new state. * Gadget will stay disconnected after activation. + * + * udc should have been started before gadget being pulled down. */ gadget->connected = false; goto out; @@ -774,6 +783,30 @@ int usb_gadget_disconnect(struct usb_gadget *gadget)

return ret; } + +/** + * usb_gadget_disconnect - software-controlled disconnect from USB host + * @gadget:the peripheral being disconnected + * + * Disables the D+ (or potentially D-) pullup, which the host may see + * as a disconnect (when a VBUS session is active). Not all systems + * support software pullup controls. + * + * Following a successful disconnect, invoke the ->disconnect() callback + * for the current gadget driver so that UDC drivers don't need to. + * + * Returns zero on success, else negative errno. + */ +int usb_gadget_disconnect(struct usb_gadget *gadget) +{ + int ret; + + mutex_lock(&gadget->udc->connect_lock); + ret = usb_gadget_disconnect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock); + + return ret; +} EXPORT_SYMBOL_GPL(usb_gadget_disconnect);

/** @@ -794,10 +827,11 @@ int usb_gadget_deactivate(struct usb_gadget *gadget) if (gadget->deactivated) goto out;

+ mutex_lock(&gadget->udc->connect_lock); if (gadget->connected) { - ret = usb_gadget_disconnect(gadget); + ret = usb_gadget_disconnect_locked(gadget); if (ret) - goto out; + goto unlock;

/* * If gadget was being connected before deactivation, we want @@ -807,6 +841,8 @@ int usb_gadget_deactivate(struct usb_gadget *gadget) } gadget->deactivated = true;

+unlock: + mutex_unlock(&gadget->udc->connect_lock); out: trace_usb_gadget_deactivate(gadget, ret);

@@ -830,6 +866,7 @@ int usb_gadget_activate(struct usb_gadget *gadget) if (!gadget->deactivated) goto out;

+ mutex_lock(&gadget->udc->connect_lock); gadget->deactivated = false;

/* @@ -837,7 +874,8 @@ int usb_gadget_activate(struct usb_gadget *gadget) * while it was being deactivated, we call usb_gadget_connect(). */ if (gadget->connected) - ret = usb_gadget_connect(gadget); + ret = usb_gadget_connect_locked(gadget); + mutex_unlock(&gadget->udc->connect_lock);

out: trace_usb_gadget_activate(gadget, ret); @@ -1078,12 +1116,13 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);

/* ------------------------------------------------------------------------- */

-static void usb_udc_connect_control(struct usb_udc *udc) +/* Acquire udc_connect_control_lock before calling this function. */ +static void usb_udc_connect_control_locked(struct usb_udc *udc) { - if (udc->vbus) - usb_gadget_connect(udc->gadget); + if (udc->vbus && udc->started) + usb_gadget_connect_locked(udc->gadget); else - usb_gadget_disconnect(udc->gadget); + usb_gadget_disconnect_locked(udc->gadget); }

/** @@ -1099,10 +1138,12 @@ void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status) { struct usb_udc *udc = gadget->udc;

+ mutex_lock(&udc->connect_lock); if (udc) { udc->vbus = status; - usb_udc_connect_control(udc); + usb_udc_connect_control_locked(udc); } + mutex_unlock(&udc->connect_lock); } EXPORT_SYMBOL_GPL(usb_udc_vbus_handler);

@@ -1124,7 +1165,7 @@ void usb_gadget_udc_reset(struct usb_gadget *gadget, EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);

/** - * usb_gadget_udc_start - tells usb device controller to start up + * usb_gadget_udc_start_locked - tells usb device controller to start up * @udc: The UDC to be started * * This call is issued by the UDC Class driver when it's about @@ -1136,7 +1177,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset); * * Returns zero on success, else negative errno. */ -static inline int usb_gadget_udc_start(struct usb_udc *udc) +static inline int usb_gadget_udc_start_locked(struct usb_udc *udc) { int ret;

@@ -1153,7 +1194,7 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc) }

/** - * usb_gadget_udc_stop - tells usb device controller we don't need it anymore + * usb_gadget_udc_stop_locked - tells usb device controller we don't need it anymore * @udc: The UDC to be stopped * * This call is issued by the UDC Class driver after calling @@ -1163,7 +1204,7 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc) * far as powering off UDC completely and disable its data * line pullups. */ -static inline void usb_gadget_udc_stop(struct usb_udc *udc) +static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc) { if (!udc->started) { dev_err(&udc->dev, "UDC had already stopped\n"); @@ -1322,6 +1363,7 @@ int usb_add_gadget(struct usb_gadget *gadget)

udc->gadget = gadget; gadget->udc = udc; + mutex_init(&udc->connect_lock);

udc->started = false;

@@ -1523,11 +1565,15 @@ static int gadget_bind_driver(struct device *dev) if (ret) goto err_bind;

- ret = usb_gadget_udc_start(udc); - if (ret) + mutex_lock(&udc->connect_lock); + ret = usb_gadget_udc_start_locked(udc); + if (ret) { + mutex_unlock(&udc->connect_lock); goto err_start; + } usb_gadget_enable_async_callbacks(udc); - usb_udc_connect_control(udc); + usb_udc_connect_control_locked(udc); + mutex_unlock(&udc->connect_lock);

kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE); return 0; @@ -1558,12 +1604,14 @@ static void gadget_unbind_driver(struct device *dev)

kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);

- usb_gadget_disconnect(gadget); + mutex_lock(&udc->connect_lock); + usb_gadget_disconnect_locked(gadget); usb_gadget_disable_async_callbacks(udc); if (gadget->irq) synchronize_irq(gadget->irq); udc->driver->unbind(gadget); - usb_gadget_udc_stop(udc); + usb_gadget_udc_stop_locked(udc); + mutex_unlock(&udc->connect_lock);

mutex_lock(&udc_lock); driver->is_bound = false; @@ -1649,11 +1697,15 @@ static ssize_t soft_connect_store(struct device *dev, }

if (sysfs_streq(buf, "connect")) { - usb_gadget_udc_start(udc); - usb_gadget_connect(udc->gadget); + mutex_lock(&udc->connect_lock); + usb_gadget_udc_start_locked(udc); + usb_gadget_connect_locked(udc->gadget); + mutex_unlock(&udc->connect_lock); } else if (sysfs_streq(buf, "disconnect")) { - usb_gadget_disconnect(udc->gadget); - usb_gadget_udc_stop(udc); + mutex_lock(&udc->connect_lock); + usb_gadget_disconnect_locked(udc->gadget); + usb_gadget_udc_stop_locked(udc); + mutex_unlock(&udc->connect_lock); } else { dev_err(dev, "unsupported command '%s'\n", buf); ret = -EINVAL;

base-commit: d629c0e221cd99198b843d8351a0a9bfec6c0423