Re: [PATCH 11/11] drm/i915: Fix undefined behavior due to shift overflowing the constant

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 18 May 2022, Borislav Petkov <bp@alien8.de> wrote:
> On Tue, May 17, 2022 at 04:05:46PM -0700, Randy Dunlap wrote:
>> 
>> 
>> On 4/5/22 08:15, Borislav Petkov wrote:
>> > From: Borislav Petkov <bp@suse.de>
>> > 
>> > Fix:
>> > 
>> >   In file included from <command-line>:0:0:
>> >   drivers/gpu/drm/i915/gt/uc/intel_guc.c: In function ‘intel_guc_send_mmio’:
>> >   ././include/linux/compiler_types.h:352:38: error: call to ‘__compiletime_assert_1047’ \
>> >   declared with attribute error: FIELD_PREP: mask is not constant
>> >     _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
>> > 
>> > and other build errors due to shift overflowing values.
>> > 
>> > See https://lore.kernel.org/r/YkwQ6%2BtIH8GQpuct@zn.tnic for the gory
>> > details as to why it triggers with older gccs only.
>> > 
>> 
>> Acked-by: Randy Dunlap <rdunlap@infradead.org>
>> Tested-by: Randy Dunlap <rdunlap@infradead.org>
>> 
>> Is this merged anywhere?
>
> It's state is "new" in their patchwork:
>
> https://patchwork.freedesktop.org/patch/480756/

Basically we run all patches through CI before merging, and because only
one patch was sent to intel-gfx, the CI just sat waiting for the rest of
the series to arrive...

Anyway, didn't really like the changes in i915_reg.h, sent my version of
that and the rest separately [1].

> so I guess not yet.
>
>> It could/should at least be in linux-next so that other people
>> don't waste time on it.
>
> -ETOOMANYPATCHES I guess. :-\

Yeah, sorry about that.


BR,
Jani.

[1] https://patchwork.freedesktop.org/series/104122/


-- 
Jani Nikula, Intel Open Source Graphics Center