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staging: most: usb: fix usb_disconnect race condition

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The functions usb_disconnect and usb_sndbulkpipe are racing for the struct
usb_device, which might cause a null pointer dereference exception. This
patch fixes this race condition by protecting the critical section inside
the function hdm_enque with the io_mutex.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christian Gromm 2018-05-08 11:45:15 +02:00 committed by Greg Kroah-Hartman
parent 9a32315b0b
commit c06b99e002
1 changed files with 14 additions and 7 deletions
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21
drivers/staging/most/usb/usb.c
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@ -565,14 +565,19 @@ static int hdm_enqueue(struct most_interface *iface, int channel,
mdev = to_mdev(iface);
conf = &mdev->conf[channel];
mutex_lock(&mdev->io_mutex);
if (!mdev->usb_device) {
retval = -ENODEV;
goto _exit;
}
dev = &mdev->usb_device->dev;
if (!mdev->usb_device)
return -ENODEV;
urb = usb_alloc_urb(NO_ISOCHRONOUS_URB, GFP_ATOMIC);
if (!urb)
return -ENOMEM;
if (!urb) {
retval = -ENOMEM;
goto _exit;
}
if ((conf->direction & MOST_CH_TX) && mdev->padding_active[channel] &&
hdm_add_padding(mdev, channel, mbo)) {
@ -613,12 +618,14 @@ static int hdm_enqueue(struct most_interface *iface, int channel,
dev_err(dev, "URB submit failed with error %d.\n", retval);
goto _error_1;
}
return 0;
goto _exit;
_error_1:
usb_unanchor_urb(urb);
_error:
usb_free_urb(urb);
_exit:
mutex_unlock(&mdev->io_mutex);
return retval;
}