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usb: gadget: udc: core: Invoke usb_gadget_connect only when started
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commit 0db213e upstream.

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.

Fixes: 628ef0d ("usb: udc: add usb_udc_vbus_handler")
Cc: stable@vger.kernel.org
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Link: https://lore.kernel.org/r/20230407030741.3163220-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@gregkh
Badhri Jagan Sridharan authored and gregkh committed May 11, 2023
1 parent b252702 commit 3852f56
Showing 1 changed file with 104 additions and 44 deletions.
148 changes: 104 additions & 44 deletions drivers/usb/gadget/udc/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand All @@ -48,6 +52,7 @@ struct usb_udc {
struct list_head list;
bool vbus;
bool started;
struct mutex connect_lock;
};

static struct class *udc_class;
Expand Down Expand Up @@ -660,17 +665,9 @@ 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 connect_lock held. */
static int usb_gadget_connect_locked(struct usb_gadget *gadget)
__must_hold(&gadget->udc->connect_lock)
{
int ret = 0;

Expand All @@ -679,10 +676,12 @@ 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;
Expand All @@ -697,22 +696,32 @@ 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 connect_lock held. */
static int usb_gadget_disconnect_locked(struct usb_gadget *gadget)
__must_hold(&gadget->udc->connect_lock)
{
int ret = 0;

Expand All @@ -724,10 +733,12 @@ 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;
Expand All @@ -747,6 +758,30 @@ 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);

/**
Expand All @@ -767,10 +802,11 @@ 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
Expand All @@ -780,6 +816,8 @@ 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);

Expand All @@ -803,14 +841,16 @@ int usb_gadget_activate(struct usb_gadget *gadget)
if (!gadget->deactivated)
goto out;

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

/*
* If gadget has been connected before deactivation, or became connected
* 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);
Expand Down Expand Up @@ -1051,12 +1091,13 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);

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

static void usb_udc_connect_control(struct usb_udc *udc)
/* Acquire connect_lock before calling this function. */
static void usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
{
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);
}

/**
Expand All @@ -1072,10 +1113,12 @@ 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);

Expand All @@ -1097,7 +1140,7 @@ 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
Expand All @@ -1108,8 +1151,11 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
* necessary to have it powered on.
*
* Returns zero on success, else negative errno.
*
* Caller should acquire connect_lock before invoking this function.
*/
static inline int usb_gadget_udc_start(struct usb_udc *udc)
static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
__must_hold(&udc->connect_lock)
{
int ret;

Expand All @@ -1126,7 +1172,7 @@ 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
Expand All @@ -1135,8 +1181,11 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc)
* The details are implementation specific, but it can go as
* far as powering off UDC completely and disable its data
* line pullups.
*
* Caller should acquire connect lock before invoking this function.
*/
static inline void usb_gadget_udc_stop(struct usb_udc *udc)
static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc)
__must_hold(&udc->connect_lock)
{
if (!udc->started) {
dev_err(&udc->dev, "UDC had already stopped\n");
Expand Down Expand Up @@ -1295,6 +1344,7 @@ int usb_add_gadget(struct usb_gadget *gadget)

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

udc->started = false;

Expand Down Expand Up @@ -1496,11 +1546,15 @@ 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;
Expand Down Expand Up @@ -1531,12 +1585,14 @@ 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;
Expand Down Expand Up @@ -1622,11 +1678,15 @@ 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;
Expand Down

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