Re: [PATCH v2 7/8] cedrus: Use vb2_find_buffer

From: Ezequiel Garcia
Date: Fri Jul 15 2022 - 07:49:02 EST

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In reply to: Nicolas Dufresne: "Re: [PATCH v2 7/8] cedrus: Use vb2_find_buffer"
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Hi Nicolas,

Thanks a lot for the test and the bug report.

On Thu, Jul 14, 2022 at 4:26 PM Nicolas Dufresne <nicolas@xxxxxxxxxxxx> wrote:
>
> Hi Ezequiel,
>
> I started testing with these patches and found some NULL dreferences, see my
> comment inline...
>
> Le lundi 11 juillet 2022 à 18:11 -0300, Ezequiel Garcia a écrit :
> > Use the newly introduced vb2_find_buffer API to get a vb2_buffer
> > given a buffer timestamp.
> >
> > Cc: Maxime Ripard <mripard@xxxxxxxxxx>
> > Cc: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx>
> > Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> > Signed-off-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx>
> > Acked-by: Tomasz Figa <tfiga@xxxxxxxxxxxx>
> > ---
> > drivers/staging/media/sunxi/cedrus/cedrus.h | 24 ++++++-----
> > .../staging/media/sunxi/cedrus/cedrus_h264.c | 16 +++----
> > .../staging/media/sunxi/cedrus/cedrus_h265.c | 16 +++----
> > .../staging/media/sunxi/cedrus/cedrus_mpeg2.c | 28 ++++--------
> > .../staging/media/sunxi/cedrus/cedrus_vp8.c | 43 ++++---------------
> > 5 files changed, 46 insertions(+), 81 deletions(-)
> >
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus.h b/drivers/staging/media/sunxi/cedrus/cedrus.h
> > index 3bc094eb497f..c054dbe3d3bc 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus.h
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus.h
> > @@ -233,19 +233,23 @@ static inline dma_addr_t cedrus_buf_addr(struct vb2_buffer *buf,
> > }
> >
> > static inline dma_addr_t cedrus_dst_buf_addr(struct cedrus_ctx *ctx,
> > - int index, unsigned int plane)
> > + struct vb2_buffer *buf,
> > + unsigned int plane)
> > {
> > - struct vb2_buffer *buf = NULL;
> > - struct vb2_queue *vq;
> > -
> > - if (index < 0)
> > - return 0;
> > + return buf ? cedrus_buf_addr(buf, &ctx->dst_fmt, plane) : 0;
> > +}
> >
> > - vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, V4L2_BUF_TYPE_VIDEO_CAPTURE);
> > - if (vq)
> > - buf = vb2_get_buffer(vq, index);
> > +static inline void cedrus_write_ref_buf_addr(struct cedrus_ctx *ctx,
> > + struct vb2_queue *q,
> > + u64 timestamp,
> > + u32 luma_reg,
> > + u32 chroma_reg)
> > +{
> > + struct cedrus_dev *dev = ctx->dev;
> > + struct vb2_buffer *buf = vb2_find_buffer(q, timestamp);
> >
> > - return buf ? cedrus_buf_addr(buf, &ctx->dst_fmt, plane) : 0;
> > + cedrus_write(dev, luma_reg, cedrus_dst_buf_addr(ctx, buf, 0));
> > + cedrus_write(dev, chroma_reg, cedrus_dst_buf_addr(ctx, buf, 1));
> > }
> >
> > static inline struct cedrus_buffer *
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > index d8fb93035470..0559efeac125 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > @@ -111,16 +111,16 @@ static void cedrus_write_frame_list(struct cedrus_ctx *ctx,
> > for (i = 0; i < ARRAY_SIZE(decode->dpb); i++) {
> > const struct v4l2_h264_dpb_entry *dpb = &decode->dpb[i];
> > struct cedrus_buffer *cedrus_buf;
> > - int buf_idx;
> > + struct vb2_buffer *buf;
> >
> > if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_VALID))
> > continue;
> >
> > - buf_idx = vb2_find_timestamp(cap_q, dpb->reference_ts, 0);
> > - if (buf_idx < 0)
> > + buf = vb2_find_buffer(cap_q, dpb->reference_ts);
> > + if (!buf)
> > continue;
> >
> > - cedrus_buf = vb2_to_cedrus_buffer(cap_q->bufs[buf_idx]);
> > + cedrus_buf = vb2_to_cedrus_buffer(buf);
> > position = cedrus_buf->codec.h264.position;
> > used_dpbs |= BIT(position);
> >
> > @@ -186,7 +186,7 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> > const struct v4l2_h264_dpb_entry *dpb;
> > const struct cedrus_buffer *cedrus_buf;
> > unsigned int position;
> > - int buf_idx;
> > + struct vb2_buffer *buf;
> > u8 dpb_idx;
> >
> > dpb_idx = ref_list[i].index;
> > @@ -195,11 +195,11 @@ static void _cedrus_write_ref_list(struct cedrus_ctx *ctx,
> > if (!(dpb->flags & V4L2_H264_DPB_ENTRY_FLAG_ACTIVE))
> > continue;
> >
> > - buf_idx = vb2_find_timestamp(cap_q, dpb->reference_ts, 0);
> > - if (buf_idx < 0)
> > + buf = vb2_find_buffer(cap_q, dpb->reference_ts);
> > + if (!buf)
> > continue;
> >
> > - cedrus_buf = vb2_to_cedrus_buffer(cap_q->bufs[buf_idx]);
> > + cedrus_buf = vb2_to_cedrus_buffer(buf);
> > position = cedrus_buf->codec.h264.position;
> >
> > sram_array[i] |= position << 1;
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > index 44f385be9f6c..60cc13e4d0a9 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > @@ -102,14 +102,14 @@ static void cedrus_h265_frame_info_write_single(struct cedrus_ctx *ctx,
> > unsigned int index,
> > bool field_pic,
> > u32 pic_order_cnt[],
> > - int buffer_index)
> > + struct vb2_buffer *buf)
> > {
> > struct cedrus_dev *dev = ctx->dev;
> > - dma_addr_t dst_luma_addr = cedrus_dst_buf_addr(ctx, buffer_index, 0);
> > - dma_addr_t dst_chroma_addr = cedrus_dst_buf_addr(ctx, buffer_index, 1);
> > + dma_addr_t dst_luma_addr = cedrus_dst_buf_addr(ctx, buf, 0);
> > + dma_addr_t dst_chroma_addr = cedrus_dst_buf_addr(ctx, buf, 1);
> > dma_addr_t mv_col_buf_addr[2] = {
> > - cedrus_h265_frame_info_mv_col_buf_addr(ctx, buffer_index, 0),
> > - cedrus_h265_frame_info_mv_col_buf_addr(ctx, buffer_index,
> > + cedrus_h265_frame_info_mv_col_buf_addr(ctx, buf->index, 0),
> > + cedrus_h265_frame_info_mv_col_buf_addr(ctx, buf->index,
> > field_pic ? 1 : 0)
>
> Previously, -1 would be passed to cedrus_h265_frame_info_mv_col_buf_addr(),
> which would not find a buffer at that index, and would return 0. Now the code
> will crash with a NULL pointer deref.
>

Is it really correct to pass -1 to cedrus_h265_frame_info_mv_col_buf_addr?
It seems it get casted into an unsigned type and then used to calculate
an address for DMA.

static inline dma_addr_t
cedrus_h265_frame_info_mv_col_buf_addr(struct cedrus_ctx *ctx,
unsigned int index, unsigned int field)
{
return ctx->codec.h265.mv_col_buf_addr + index *
ctx->codec.h265.mv_col_buf_unit_size +
field * ctx->codec.h265.mv_col_buf_unit_size / 2;
}

Fixing the driver to go back to the previous behavior is trivial,
but this looks odd.

Jernej, Paul, any thoughts?

Thanks,
Ezequiel

> > };
> > u32 offset = VE_DEC_H265_SRAM_OFFSET_FRAME_INFO +
> > @@ -141,7 +141,7 @@ static void cedrus_h265_frame_info_write_dpb(struct cedrus_ctx *ctx,
> > unsigned int i;
> >
> > for (i = 0; i < num_active_dpb_entries; i++) {
> > - int buffer_index = vb2_find_timestamp(vq, dpb[i].timestamp, 0);
> > + struct vb2_buffer *buf = vb2_find_buffer(vq, dpb[i].timestamp);
> > u32 pic_order_cnt[2] = {
> > dpb[i].pic_order_cnt[0],
> > dpb[i].pic_order_cnt[1]
> > @@ -149,7 +149,7 @@ static void cedrus_h265_frame_info_write_dpb(struct cedrus_ctx *ctx,
> >
> > cedrus_h265_frame_info_write_single(ctx, i, dpb[i].field_pic,
> > pic_order_cnt,
> > - buffer_index);
> > + buf);
> > }
> > }
> >
> > @@ -616,7 +616,7 @@ static void cedrus_h265_setup(struct cedrus_ctx *ctx,
> > cedrus_h265_frame_info_write_single(ctx, output_pic_list_index,
> > slice_params->pic_struct != 0,
> > pic_order_cnt,
> > - run->dst->vb2_buf.index);
> > + &run->dst->vb2_buf);
> >
> > cedrus_write(dev, VE_DEC_H265_OUTPUT_FRAME_IDX, output_pic_list_index);
> >
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> > index 5dad2f296c6d..22d6cae9a710 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_mpeg2.c
> > @@ -54,13 +54,9 @@ static void cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
> > const struct v4l2_ctrl_mpeg2_picture *pic;
> > const struct v4l2_ctrl_mpeg2_quantisation *quantisation;
> > dma_addr_t src_buf_addr, dst_luma_addr, dst_chroma_addr;
> > - dma_addr_t fwd_luma_addr, fwd_chroma_addr;
> > - dma_addr_t bwd_luma_addr, bwd_chroma_addr;
> > struct cedrus_dev *dev = ctx->dev;
> > struct vb2_queue *vq;
> > const u8 *matrix;
> > - int forward_idx;
> > - int backward_idx;
> > unsigned int i;
> > u32 reg;
> >
> > @@ -123,27 +119,19 @@ static void cedrus_mpeg2_setup(struct cedrus_ctx *ctx, struct cedrus_run *run)
> > cedrus_write(dev, VE_DEC_MPEG_PICBOUNDSIZE, reg);
> >
> > /* Forward and backward prediction reference buffers. */
> > -
> > vq = v4l2_m2m_get_vq(ctx->fh.m2m_ctx, V4L2_BUF_TYPE_VIDEO_CAPTURE);
> >
> > - forward_idx = vb2_find_timestamp(vq, pic->forward_ref_ts, 0);
> > - fwd_luma_addr = cedrus_dst_buf_addr(ctx, forward_idx, 0);
> > - fwd_chroma_addr = cedrus_dst_buf_addr(ctx, forward_idx, 1);
> > -
> > - cedrus_write(dev, VE_DEC_MPEG_FWD_REF_LUMA_ADDR, fwd_luma_addr);
> > - cedrus_write(dev, VE_DEC_MPEG_FWD_REF_CHROMA_ADDR, fwd_chroma_addr);
> > -
> > - backward_idx = vb2_find_timestamp(vq, pic->backward_ref_ts, 0);
> > - bwd_luma_addr = cedrus_dst_buf_addr(ctx, backward_idx, 0);
> > - bwd_chroma_addr = cedrus_dst_buf_addr(ctx, backward_idx, 1);
> > -
> > - cedrus_write(dev, VE_DEC_MPEG_BWD_REF_LUMA_ADDR, bwd_luma_addr);
> > - cedrus_write(dev, VE_DEC_MPEG_BWD_REF_CHROMA_ADDR, bwd_chroma_addr);
> > + cedrus_write_ref_buf_addr(ctx, vq, pic->forward_ref_ts,
> > + VE_DEC_MPEG_FWD_REF_LUMA_ADDR,
> > + VE_DEC_MPEG_FWD_REF_CHROMA_ADDR);
> > + cedrus_write_ref_buf_addr(ctx, vq, pic->backward_ref_ts,
> > + VE_DEC_MPEG_BWD_REF_LUMA_ADDR,
> > + VE_DEC_MPEG_BWD_REF_CHROMA_ADDR);
> >
> > /* Destination luma and chroma buffers. */
> >
> > - dst_luma_addr = cedrus_dst_buf_addr(ctx, run->dst->vb2_buf.index, 0);
> > - dst_chroma_addr = cedrus_dst_buf_addr(ctx, run->dst->vb2_buf.index, 1);
> > + dst_luma_addr = cedrus_dst_buf_addr(ctx, &run->dst->vb2_buf, 0);
> > + dst_chroma_addr = cedrus_dst_buf_addr(ctx, &run->dst->vb2_buf, 1);
> >
> > cedrus_write(dev, VE_DEC_MPEG_REC_LUMA, dst_luma_addr);
> > cedrus_write(dev, VE_DEC_MPEG_REC_CHROMA, dst_chroma_addr);
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_vp8.c b/drivers/staging/media/sunxi/cedrus/cedrus_vp8.c
> > index f4016684b32d..196cf692186d 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_vp8.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_vp8.c
> > @@ -661,7 +661,6 @@ static void cedrus_vp8_setup(struct cedrus_ctx *ctx,
> > dma_addr_t luma_addr, chroma_addr;
> > dma_addr_t src_buf_addr;
> > int header_size;
> > - int qindex;
> > u32 reg;
> >
> > cedrus_engine_enable(ctx, CEDRUS_CODEC_VP8);
> > @@ -805,43 +804,17 @@ static void cedrus_vp8_setup(struct cedrus_ctx *ctx,
> > reg |= VE_VP8_LF_DELTA0(slice->lf.mb_mode_delta[0]);
> > cedrus_write(dev, VE_VP8_MODE_LF_DELTA, reg);
> >
> > - luma_addr = cedrus_dst_buf_addr(ctx, run->dst->vb2_buf.index, 0);
> > - chroma_addr = cedrus_dst_buf_addr(ctx, run->dst->vb2_buf.index, 1);
> > + luma_addr = cedrus_dst_buf_addr(ctx, &run->dst->vb2_buf, 0);
> > + chroma_addr = cedrus_dst_buf_addr(ctx, &run->dst->vb2_buf, 1);
> > cedrus_write(dev, VE_VP8_REC_LUMA, luma_addr);
> > cedrus_write(dev, VE_VP8_REC_CHROMA, chroma_addr);
> >
> > - qindex = vb2_find_timestamp(cap_q, slice->last_frame_ts, 0);
> > - if (qindex >= 0) {
> > - luma_addr = cedrus_dst_buf_addr(ctx, qindex, 0);
> > - chroma_addr = cedrus_dst_buf_addr(ctx, qindex, 1);
> > - cedrus_write(dev, VE_VP8_FWD_LUMA, luma_addr);
> > - cedrus_write(dev, VE_VP8_FWD_CHROMA, chroma_addr);
> > - } else {
> > - cedrus_write(dev, VE_VP8_FWD_LUMA, 0);
> > - cedrus_write(dev, VE_VP8_FWD_CHROMA, 0);
> > - }
> > -
> > - qindex = vb2_find_timestamp(cap_q, slice->golden_frame_ts, 0);
> > - if (qindex >= 0) {
> > - luma_addr = cedrus_dst_buf_addr(ctx, qindex, 0);
> > - chroma_addr = cedrus_dst_buf_addr(ctx, qindex, 1);
> > - cedrus_write(dev, VE_VP8_BWD_LUMA, luma_addr);
> > - cedrus_write(dev, VE_VP8_BWD_CHROMA, chroma_addr);
> > - } else {
> > - cedrus_write(dev, VE_VP8_BWD_LUMA, 0);
> > - cedrus_write(dev, VE_VP8_BWD_CHROMA, 0);
> > - }
> > -
> > - qindex = vb2_find_timestamp(cap_q, slice->alt_frame_ts, 0);
> > - if (qindex >= 0) {
> > - luma_addr = cedrus_dst_buf_addr(ctx, qindex, 0);
> > - chroma_addr = cedrus_dst_buf_addr(ctx, qindex, 1);
> > - cedrus_write(dev, VE_VP8_ALT_LUMA, luma_addr);
> > - cedrus_write(dev, VE_VP8_ALT_CHROMA, chroma_addr);
> > - } else {
> > - cedrus_write(dev, VE_VP8_ALT_LUMA, 0);
> > - cedrus_write(dev, VE_VP8_ALT_CHROMA, 0);
> > - }
> > + cedrus_write_ref_buf_addr(ctx, cap_q, slice->last_frame_ts,
> > + VE_VP8_FWD_LUMA, VE_VP8_FWD_CHROMA);
> > + cedrus_write_ref_buf_addr(ctx, cap_q, slice->golden_frame_ts,
> > + VE_VP8_BWD_LUMA, VE_VP8_BWD_CHROMA);
> > + cedrus_write_ref_buf_addr(ctx, cap_q, slice->alt_frame_ts,
> > + VE_VP8_ALT_LUMA, VE_VP8_ALT_CHROMA);
> >
> > cedrus_write(dev, VE_H264_CTRL, VE_H264_CTRL_VP8 |
> > VE_H264_CTRL_DECODE_ERR_INT |
>

Next message: Paolo Bonzini: "[PATCH] KVM: emulate: do not adjust size of fastop and setcc subroutines"
Previous message: Vinod Koul: "Re: [PATCH] phy: rockchip-inno-usb2: Ignore OTG IRQs in host mode"
In reply to: Nicolas Dufresne: "Re: [PATCH v2 7/8] cedrus: Use vb2_find_buffer"
Next in thread: Ezequiel Garcia: "[PATCH v2 8/8] videobuf2: Remove vb2_find_timestamp()"
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