Dne četrtek, 18. avgust 2022 ob 22:33:08 CEST je Nicolas Dufresne napisal(a):
> From: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
>
> The busy status bit may never de-assert if number of programmed skip
> bits is incorrect, resulting in a kernel hang because the bit is polled
> endlessly in the code. Fix it by adding timeout for the bit-polling.
> This problem is reproducible by setting the data_bit_offset field of
> the HEVC slice params to a wrong value by userspace.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@xxxxxxxxxxxxx>
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@xxxxxxxxxxxxx>
Fixes tag would be nice.
> ---
> drivers/staging/media/sunxi/cedrus/cedrus_h265.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c index
> f703c585d91c5..f0bc118021b0a 100644
> --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> @@ -227,6 +227,7 @@ static void cedrus_h265_pred_weight_write(struct
> cedrus_dev *dev, static void cedrus_h265_skip_bits(struct cedrus_dev *dev,
> int num) {
> int count = 0;
> + u32 reg;
>
> while (count < num) {
> int tmp = min(num - count, 32);
> @@ -234,8 +235,9 @@ static void cedrus_h265_skip_bits(struct cedrus_dev
> *dev, int num) cedrus_write(dev, VE_DEC_H265_TRIGGER,
> VE_DEC_H265_TRIGGER_FLUSH_BITS |
> VE_DEC_H265_TRIGGER_TYPE_N_BITS(tmp));
> - while (cedrus_read(dev, VE_DEC_H265_STATUS) &
> VE_DEC_H265_STATUS_VLD_BUSY) - udelay(1);
> +
> + if (cedrus_wait_for(dev, VE_DEC_H265_STATUS,
> VE_DEC_H265_STATUS_VLD_BUSY)) +
dev_err_ratelimited(dev->dev, "timed out
> waiting to skip bits\n");
Reporting issue is nice, but better would be to propagate error, since there
is no way to properly decode this slice if above code block fails.
Best regards,
Jernej
>
> count += tmp;
> }
