From: Dan Vacura w36195@motorola.com
commit 71d471e3faf90c9674cadc7605ac719e82cb7fac upstream.
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buf_used) of the active buffer (no longer active) is not reset.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") Cc: stable@vger.kernel.org Signed-off-by: Dan Vacura w36195@motorola.com Link: https://lore.kernel.org/r/20220331184024.23918-1-w36195@motorola.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/function/uvc_queue.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/usb/gadget/function/uvc_queue.c +++ b/drivers/usb/gadget/function/uvc_queue.c @@ -242,6 +242,8 @@ void uvcg_queue_cancel(struct uvc_video_ 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