Messages in this thread | | | From | Jernej Škrabec <> | Subject | Re: [PATCH v1 3/3] media: cedrus: Fix endless loop in cedrus_h265_skip_bits() | Date | Fri, 19 Aug 2022 06:16:12 +0200 |
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Dne četrtek, 18. avgust 2022 ob 22:33:08 CEST je Nicolas Dufresne napisal(a): > From: Dmitry Osipenko <dmitry.osipenko@collabora.com> > > 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@vger.kernel.org > Reported-by: Nicolas Dufresne <nicolas.dufresne@collabora.com> > Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> > Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
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; > }
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