Hi Dan,
On 04.04.2019 17:42, Dan Carpenter wrote:
> Hello Andrzej Hajda,
>
> The patch 4d0b0ed63660: "[media] s5p-mfc: use MFC_BUF_FLAG_EOS to
> identify last buffers in decoder capture queue" from Oct 7, 2015,
> leads to the following static checker warning:
>
> drivers/media/platform/s5p-mfc/s5p_mfc_dec.c:664 vidioc_dqbuf()
> warn: uncapped user index 'ctx->dst_bufs[buf->index]'
Almost identical e-mail you have sent about year ago, and me and Hans
have explained you that it is false positive.
Has something changed?
Regards
Andrzej
>
> drivers/media/platform/s5p-mfc/s5p_mfc_dec.c
> 642 static int vidioc_dqbuf(struct file *file, void *priv, struct
> v4l2_buffer *buf)
> 643 {
> 644 const struct v4l2_event ev = {
> 645 .type = V4L2_EVENT_EOS
> 646 };
> 647 struct s5p_mfc_ctx *ctx = fh_to_ctx(priv);
> 648 int ret;
> 649
> 650 if (ctx->state == MFCINST_ERROR) {
> 651 mfc_err_limited("Call on DQBUF after unrecoverable
> error\n");
> 652 return -EIO;
> 653 }
> 654
> 655 switch (buf->type) {
> 656 case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
> 657 return vb2_dqbuf(&ctx->vq_src, buf, file->f_flags &
> O_NONBLOCK);
> 658 case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
> 659 ret = vb2_dqbuf(&ctx->vq_dst, buf, file->f_flags &
> O_NONBLOCK);
> 660 if (ret)
> 661 return ret;
> 662
> 663 if (ctx->state == MFCINST_FINISHED &&
> --> 664 (ctx->dst_bufs[buf->index].flags &
> MFC_BUF_FLAG_EOS))
> ^^^^^^^^^^
> Smatch is saying that this isn't capped. The truth is that v4l2 code is
> a bit complicated for Smatch, but in this case I can't see where
> "buf->index" does get capped. I would have expected it to be capped in
> check_array_args() where we check "buf->length" but it's not.
>
> I've been going through these warnings really carefully in the past
> couple weeks trying to fix false positives so let me know what I'm
> missing and I will update the check. Even if I have to manually muck
> in the DB.
>
> 665 v4l2_event_queue_fh(&ctx->fh, &ev);
> 666 return 0;
> 667 default:
> 668 return -EINVAL;
> 669 }
> 670 }
>
> regards,
> dan carpenter
>
>
