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Subject[PATCH 5.10 169/530] usb: gadget: pch_udc: Check if driver is present before calling ->setup()
Date
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit fbdbbe6d3ee502b3bdeb4f255196bb45003614be ]

Since we have a separate routine for VBUS sense, the interrupt may occur
before gadget driver is present. Hence, ->setup() call may oops the kernel:

[ 55.245843] BUG: kernel NULL pointer dereference, address: 00000010
...
[ 55.245843] EIP: pch_udc_isr.cold+0x162/0x33f
...
[ 55.245843] <IRQ>
[ 55.245843] ? pch_udc_svc_data_out+0x160/0x160

Check if driver is present before calling ->setup().

Fixes: f646cf94520e ("USB device driver of Topcliff PCH")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210323153626.54908-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/gadget/udc/pch_udc.c | 28 ++++++++++++++++++----------
1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/gadget/udc/pch_udc.c b/drivers/usb/gadget/udc/pch_udc.c
index f6f8965c4f8c..b46e9bdc720f 100644
--- a/drivers/usb/gadget/udc/pch_udc.c
+++ b/drivers/usb/gadget/udc/pch_udc.c
@@ -2307,6 +2307,21 @@ static void pch_udc_svc_data_out(struct pch_udc_dev *dev, int ep_num)
pch_udc_set_dma(dev, DMA_DIR_RX);
}

+static int pch_udc_gadget_setup(struct pch_udc_dev *dev)
+ __must_hold(&dev->lock)
+{
+ int rc;
+
+ /* In some cases we can get an interrupt before driver gets setup */
+ if (!dev->driver)
+ return -ESHUTDOWN;
+
+ spin_unlock(&dev->lock);
+ rc = dev->driver->setup(&dev->gadget, &dev->setup_data);
+ spin_lock(&dev->lock);
+ return rc;
+}
+
/**
* pch_udc_svc_control_in() - Handle Control IN endpoint interrupts
* @dev: Reference to the device structure
@@ -2378,15 +2393,12 @@ static void pch_udc_svc_control_out(struct pch_udc_dev *dev)
dev->gadget.ep0 = &dev->ep[UDC_EP0IN_IDX].ep;
else /* OUT */
dev->gadget.ep0 = &ep->ep;
- spin_lock(&dev->lock);
/* If Mass storage Reset */
if ((dev->setup_data.bRequestType == 0x21) &&
(dev->setup_data.bRequest == 0xFF))
dev->prot_stall = 0;
/* call gadget with setup data received */
- setup_supported = dev->driver->setup(&dev->gadget,
- &dev->setup_data);
- spin_unlock(&dev->lock);
+ setup_supported = pch_udc_gadget_setup(dev);

if (dev->setup_data.bRequestType & USB_DIR_IN) {
ep->td_data->status = (ep->td_data->status &
@@ -2634,9 +2646,7 @@ static void pch_udc_svc_intf_interrupt(struct pch_udc_dev *dev)
dev->ep[i].halted = 0;
}
dev->stall = 0;
- spin_unlock(&dev->lock);
- dev->driver->setup(&dev->gadget, &dev->setup_data);
- spin_lock(&dev->lock);
+ pch_udc_gadget_setup(dev);
}

/**
@@ -2671,9 +2681,7 @@ static void pch_udc_svc_cfg_interrupt(struct pch_udc_dev *dev)
dev->stall = 0;

/* call gadget zero with setup data received */
- spin_unlock(&dev->lock);
- dev->driver->setup(&dev->gadget, &dev->setup_data);
- spin_lock(&dev->lock);
+ pch_udc_gadget_setup(dev);
}

/**
--
2.30.2


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