Hi Sebastian, On Tue, Nov 19, 2024 at 12:02:26PM +0100, Sebastian Fricke wrote: > Hey Nathan, > > On 18.11.2024 13:06, Nathan Chancellor wrote: > > On Fri, Oct 18, 2024 at 03:14:42PM +0000, Arnd Bergmann wrote: > > > From: Arnd Bergmann <arnd@xxxxxxxx> > > > > > > With KASAN enabled, clang fails to optimize the inline version of > > > vdec_vp9_slice_map_counts_eob_coef() properly, leading to kilobytes > > > of temporary values spilled to the stack: > > > > > > drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c:1526:12: error: stack frame size (2160) exceeds limit (2048) in 'vdec_vp9_slice_update_prob' [-Werror,-Wframe-larger-than] > > > > > > This seems to affect all versions of clang including the latest (clang-20), > > > but the degree of stack overhead is different per release. > > > > > > Marking the function as noinline_for_stack is harmless here and avoids > > > the problem completely. > > > > > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > > > > Unfortunately, I have seen no moment on my upstream report and this > > warning is breaking allmodconfig builds because of -Werror. Can this be > > applied as a workaround for now (preferrably with a Cc: stable on it)? > > > > Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> > > I'll handle it asap, it will be part of 6.13 Is there any update here? I don't see this patch applied in -next. Cheers, Nathan > > > --- > > > I have not come to a conclusion on how exactly clang fails to do this > > > right, but can provide the .config and/or preprocessed source files > > > and command line if we think this should be fixed in clang. > > > --- > > > .../mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c > > > index eea709d93820..47c302745c1d 100644 > > > --- a/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c > > > +++ b/drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_vp9_req_lat_if.c > > > @@ -1188,7 +1188,8 @@ static int vdec_vp9_slice_setup_lat(struct vdec_vp9_slice_instance *instance, > > > return ret; > > > } > > > > > > -static > > > +/* clang stack usage explodes if this is inlined */ > > > +static noinline_for_stack > > > void vdec_vp9_slice_map_counts_eob_coef(unsigned int i, unsigned int j, unsigned int k, > > > struct vdec_vp9_slice_frame_counts *counts, > > > struct v4l2_vp9_frame_symbol_counts *counts_helper) > > > -- > > > 2.39.5 > > > > >
