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@xxxxxxxxxxxxx>
---
drivers/staging/most/usb/usb.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/staging/most/usb/usb.c b/drivers/staging/most/usb/usb.c
index d102b08..19ad618 100644
--- a/drivers/staging/most/usb/usb.c
+++ b/drivers/staging/most/usb/usb.c
@@ -565,14 +565,19 @@ static int hdm_enqueue(struct most_interface *iface, int channel,
mdev = to_mdev(iface);
conf = &mdev->conf[channel];
- dev = &mdev->usb_device->dev;
- if (!mdev->usb_device)
- return -ENODEV;
+ mutex_lock(&mdev->io_mutex);
+ if (!mdev->usb_device) {
+ retval = -ENODEV;
+ goto _exit;
+ }
+ dev = &mdev->usb_device->dev;
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;
}
--
2.7.4
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