From: Zheyu Ma zheyuma97@gmail.com
[ Upstream commit 2b064d91440b33fba5b452f2d1b31f13ae911d71 ]
When the driver calls cx88_risc_buffer() to prepare the buffer, the function call may fail, resulting in a empty buffer and null-ptr-deref later in buffer_queue().
The following log can reveal it:
[ 41.822762] general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI [ 41.824488] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] [ 41.828027] RIP: 0010:buffer_queue+0xc2/0x500 [ 41.836311] Call Trace: [ 41.836945] __enqueue_in_driver+0x141/0x360 [ 41.837262] vb2_start_streaming+0x62/0x4a0 [ 41.838216] vb2_core_streamon+0x1da/0x2c0 [ 41.838516] __vb2_init_fileio+0x981/0xbc0 [ 41.839141] __vb2_perform_fileio+0xbf9/0x1120 [ 41.840072] vb2_fop_read+0x20e/0x400 [ 41.840346] v4l2_read+0x215/0x290 [ 41.840603] vfs_read+0x162/0x4c0
Fix this by checking the return value of cx88_risc_buffer()
[hverkuil: fix coding style issues]
Signed-off-by: Zheyu Ma zheyuma97@gmail.com Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/pci/cx88/cx88-vbi.c | 9 +++--- drivers/media/pci/cx88/cx88-video.c | 43 +++++++++++++++-------------- 2 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/drivers/media/pci/cx88/cx88-vbi.c b/drivers/media/pci/cx88/cx88-vbi.c index a075788c64d4..469aeaa725ad 100644 --- a/drivers/media/pci/cx88/cx88-vbi.c +++ b/drivers/media/pci/cx88/cx88-vbi.c @@ -144,11 +144,10 @@ static int buffer_prepare(struct vb2_buffer *vb) return -EINVAL; vb2_set_plane_payload(vb, 0, size);
- cx88_risc_buffer(dev->pci, &buf->risc, sgt->sgl, - 0, VBI_LINE_LENGTH * lines, - VBI_LINE_LENGTH, 0, - lines); - return 0; + return cx88_risc_buffer(dev->pci, &buf->risc, sgt->sgl, + 0, VBI_LINE_LENGTH * lines, + VBI_LINE_LENGTH, 0, + lines); }
static void buffer_finish(struct vb2_buffer *vb) diff --git a/drivers/media/pci/cx88/cx88-video.c b/drivers/media/pci/cx88/cx88-video.c index c17ad9f7d822..99c55109c1e0 100644 --- a/drivers/media/pci/cx88/cx88-video.c +++ b/drivers/media/pci/cx88/cx88-video.c @@ -431,6 +431,7 @@ static int queue_setup(struct vb2_queue *q,
static int buffer_prepare(struct vb2_buffer *vb) { + int ret; struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb); struct cx8800_dev *dev = vb->vb2_queue->drv_priv; struct cx88_core *core = dev->core; @@ -445,35 +446,35 @@ static int buffer_prepare(struct vb2_buffer *vb)
switch (core->field) { case V4L2_FIELD_TOP: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, 0, UNSET, - buf->bpl, 0, core->height); + ret = cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, 0, UNSET, + buf->bpl, 0, core->height); break; case V4L2_FIELD_BOTTOM: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, UNSET, 0, - buf->bpl, 0, core->height); + ret = cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, UNSET, 0, + buf->bpl, 0, core->height); break; case V4L2_FIELD_SEQ_TB: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, - 0, buf->bpl * (core->height >> 1), - buf->bpl, 0, - core->height >> 1); + ret = cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, + 0, buf->bpl * (core->height >> 1), + buf->bpl, 0, + core->height >> 1); break; case V4L2_FIELD_SEQ_BT: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, - buf->bpl * (core->height >> 1), 0, - buf->bpl, 0, - core->height >> 1); + ret = cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, + buf->bpl * (core->height >> 1), 0, + buf->bpl, 0, + core->height >> 1); break; case V4L2_FIELD_INTERLACED: default: - cx88_risc_buffer(dev->pci, &buf->risc, - sgt->sgl, 0, buf->bpl, - buf->bpl, buf->bpl, - core->height >> 1); + ret = cx88_risc_buffer(dev->pci, &buf->risc, + sgt->sgl, 0, buf->bpl, + buf->bpl, buf->bpl, + core->height >> 1); break; } dprintk(2, @@ -481,7 +482,7 @@ static int buffer_prepare(struct vb2_buffer *vb) buf, buf->vb.vb2_buf.index, __func__, core->width, core->height, dev->fmt->depth, dev->fmt->fourcc, (unsigned long)buf->risc.dma); - return 0; + return ret; }
static void buffer_finish(struct vb2_buffer *vb)