Hans Verkuil <hverkuil@xxxxxxxxx> wrote on Mon [2019-Sep-30 10:35:05 +0200]: > On 9/27/19 8:36 PM, Benoit Parrot wrote: > > v4l2-compliance fails with this message: > > > > warn: v4l2-test-formats.cpp(717): \ > > TRY_FMT cannot handle an invalid pixelformat. > > test VIDIOC_TRY_FMT: FAIL > > > > This causes the following kernel panic: > > > > Unable to handle kernel paging request at virtual address 56595561 > > pgd = ecd80e00 > > *pgd=00000000 > > Internal error: Oops: 205 [#1] PREEMPT SMP ARM > > ... > > CPU: 0 PID: 930 Comm: v4l2-compliance Not tainted \ > > 4.14.62-01715-gc8cd67f49a19 #1 > > Hardware name: Generic DRA72X (Flattened Device Tree) > > task: ece44d80 task.stack: ecc6e000 > > PC is at __vpe_try_fmt+0x18c/0x2a8 [ti_vpe] > > LR is at 0x8 > > > > Because the driver fails to properly check the 'num_planes' values for > > proper ranges it ends up accessing out of bound data causing the kernel > > panic. > > > > Since this driver only handle single or dual plane pixel format, make > > sure the provided value does not exceed 2 planes. > > > > Signed-off-by: Benoit Parrot <bparrot@xxxxxx> > > Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> > > --- > > drivers/media/platform/ti-vpe/vpe.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/media/platform/ti-vpe/vpe.c b/drivers/media/platform/ti-vpe/vpe.c > > index bbbf11174e16..1278d457f753 100644 > > --- a/drivers/media/platform/ti-vpe/vpe.c > > +++ b/drivers/media/platform/ti-vpe/vpe.c > > @@ -1650,7 +1650,7 @@ static int __vpe_try_fmt(struct vpe_ctx *ctx, struct v4l2_format *f, > > &pix->height, MIN_H, MAX_H, H_ALIGN, > > S_ALIGN); > > > > - if (!pix->num_planes) > > + if (!pix->num_planes || pix->num_planes > 2) > > pix->num_planes = fmt->coplanar ? 2 : 1; > > else if (pix->num_planes > 1 && !fmt->coplanar) > > pix->num_planes = 1; > > > > This looks weird. > > Why not just unconditionally do: > > pix->num_planes = fmt->coplanar ? 2 : 1; In order to not change the behavior, VPE would assume that NV12 format for instance were always sent as 2 separate planes buffers. So for backward compatibility this is order to handle both cases where NV12 could be handled as both a single plane and a dual plane buffers based on what the user space application intent on passing in/out. Benoit > > Regards, > > Hans
