Hi Kees,

On Mon, 28 Feb 2022 15:02:48 -0800 Kees Cook keescook@chromium.org wrote:

On Tue, Mar 01, 2022 at 09:27:30AM +1100, Stephen Rothwell wrote:

...

After merging the kspp tree, today's linux-next build (x86_64 allmodconfig) failed like this:

drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_pcon_dsc_bpp_incr': drivers/gpu/drm/drm_dp_helper.c:3130:28: error: array subscript 12 is outside array bounds of 'const u8[12]' {aka 'const unsigned char[12]'} [-Werror=array-bounds] 3130 | buf = pcon_dsc_dpcd[DP_PCON_DSC_BPP_INCR - DP_PCON_DSC_ENCODER]; | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:3126:39: note: while referencing 'pcon_dsc_dpcd' 3126 | int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 59 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors

I can't see what in the kspp tree suddenly brought this on, so I have used the kspp tree from next-20220228 for today.

In case it matters: x86_64-linux-gnu-gcc (Debian 11.2.0-9) 11.2.0

This is fixed in drm-misc:

https://cgit.freedesktop.org/drm/drm-misc/log/ https://cgit.freedesktop.org/drm/drm-misc/commit/?id=d4da1f27396fb1dde079447... https://cgit.freedesktop.org/drm/drm-misc/commit/?id=a2151490cc6c57b368d7974...

but I had to drop the fix from the for-next/kspp because the patched file got moved in drm-misc.

Well, I moved the kspp tree to the end of the -next merges today, so it would be after all the drm changes. Unfortunately, it still fails:

drivers/gpu/drm/dp/drm_dp.c: In function 'drm_dp_pcon_dsc_bpp_incr': drivers/gpu/drm/dp/drm_dp.c:3214:28: error: array subscript 12 is outside array bounds of 'const u8[12]' {aka 'const unsigned char[12]'} [-Werror=array-bounds] 3214 | buf = pcon_dsc_dpcd[DP_PCON_DSC_BPP_INCR - DP_PCON_DSC_ENCODER]; | ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/dp/drm_dp.c:3210:39: note: while referencing 'pcon_dsc_dpcd' 3210 | int drm_dp_pcon_dsc_bpp_incr(const u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE]) | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/dp/drm_dp.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/dp/drm_dp.c:60:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 60 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/dp/drm_dp.c:211:51: note: while referencing 'link_status' 211 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Presumably the above fixes have not hit the drm trees in linux-next yet :-(

So, I used the version of your tree from next-20220228 again. This does not get the above, but does produce the error reported in https://lore.kernel.org/lkml/20220225164231.904173-1-broonie@kernel.org/ (I was wondering why that went away today) for which I have applied the patch in https://lore.kernel.org/all/20220228081421.1504213-1-hsinyi@chromium.org/