During the uvcg_video_pump() process, if an error occurs and
uvcg_queue_cancel() is called, the buffer queue will be cleared out, but
the current marker (queue->buf_used) of the active buffer (no longer
active) is not reset. On the next iteration of uvcg_video_pump() the
stale buf_used count will be used and the logic of min((unsigned
int)len, buf->bytesused - queue->buf_used) may incorrectly calculate a
nbytes size, causing an invalid memory access.
[80802.185460][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
[80802.185519][ T315] configfs-gadget gadget: uvc: VS request completed
with status -18.
...
uvcg_queue_cancel() is called and the queue is cleared out, but the
marker queue->buf_used is not reset.
...
[80802.262328][ T8682] Unable to handle kernel paging request at virtual
address ffffffc03af9f000
...
...
[80802.263138][ T8682] Call trace:
[80802.263146][ T8682] __memcpy+0x12c/0x180
[80802.263155][ T8682] uvcg_video_pump+0xcc/0x1e0
[80802.263165][ T8682] process_one_work+0x2cc/0x568
[80802.263173][ T8682] worker_thread+0x28c/0x518
[80802.263181][ T8682] kthread+0x160/0x170
[80802.263188][ T8682] ret_from_fork+0x10/0x18
[80802.263198][ T8682] Code: a8c12829 a88130cb a8c130
Fixes: d692522577c0 ("usb: gadget/uvc: Port UVC webcam gadget to use videobuf2 framework")
Signed-off-by: Dan Vacura <w36195@xxxxxxxxxxxx>
---
Changes in v2:
- Add Fixes tag
drivers/usb/gadget/function/uvc_queue.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_queue.c b/drivers/usb/gadget/function/uvc_queue.c
index d852ac9e47e7..2cda982f3765 100644
--- a/drivers/usb/gadget/function/uvc_queue.c
+++ b/drivers/usb/gadget/function/uvc_queue.c
@@ -264,6 +264,8 @@ void uvcg_queue_cancel(struct uvc_video_queue *queue, int disconnect)
buf->state = UVC_BUF_STATE_ERROR;
vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_ERROR);
}
+ queue->buf_used = 0;
+
/* This must be protected by the irqlock spinlock to avoid race
* conditions between uvc_queue_buffer and the disconnection event that
* could result in an interruptible wait in uvc_dequeue_buffer. Do not
--
2.32.0
