Hi Arnd, 2017-03-16 23:23 GMT+09:00 Arnd Bergmann <arnd@xxxxxxxx>: > On Tue, Mar 14, 2017 at 9:52 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote: >> On Tue, Mar 14, 2017 at 5:17 PM, Masahiro Yamada >> <yamada.masahiro@xxxxxxxxxxxxx> wrote: >>> Hi Arnd, >>> >>> 2017-01-14 0:40 GMT+09:00 Arnd Bergmann <arnd@xxxxxxxx>: >>>> In commit a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning >>>> for "make W=1""), I reverted another change that happened to fix a problem >>>> with old compilers, and now we get this report again with old compilers >>>> (prior to gcc-4.8) and GCOV enabled: >>>> >>>> cc1: warnings being treated as errors >>>> drivers/gpu/drm/i915/intel_ringbuffer.c: In function 'intel_ring_setup_status_page': >>>> drivers/gpu/drm/i915/intel_ringbuffer.c:438: error: 'mmio.reg' may be used uninitialized in this function >>>> At top level: >>>>>> cc1: error: unrecognized command line option "-Wno-maybe-uninitialized" >>>> >>>> The problem is that we turn off the warning conditionally in a number >>>> of places as we should, but one of them does it unconditionally. >>>> Instead, change it to call cc-disable-warning as we do elsewhere. >>>> >>>> The original patch that caused it was merged into linux-4.7, then >>>> 4.8 removed the change and 4.9 brought it back, so we probably want >>>> a backport to 4.9 once this is merged. >>>> >>>> Cc: stable@xxxxxxxxxxxxxxx >>>> Fixes: a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"") >>>> Fixes: e72e2dfe7c16 ("gcov: disable -Wmaybe-uninitialized warning") >>>> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> >>>> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> >>> >>> >>> Applied to linux-kbuild/fixes. > > Hmm, after I've carried this patch for months, I now found that it > caused a build > time regression. I'm sending a fix for that too, please either apply the fix > on top, or fold it into the first patch. > It is good that I had forgot to push my branch. I will squash the two. I'd like to combine the two git-log. The git-log of the squashed one will be like follows. If you want to edit it more, please let me know. Thanks! ---------------------------------------->8------------------------------------- build: use cc-disable-warning consistently for maybe-uninitialized In commit a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning for "make W=1""), I reverted another change that happened to fix a problem with old compilers, and now we get this report again with old compilers (prior to gcc-4.8) and GCOV enabled: cc1: warnings being treated as errors drivers/gpu/drm/i915/intel_ringbuffer.c: In function 'intel_ring_setup_status_page': drivers/gpu/drm/i915/intel_ringbuffer.c:438: error: 'mmio.reg' may be used uninitialized in this function At top level: >> cc1: error: unrecognized command line option "-Wno-maybe-uninitialized" The problem is that we turn off the warning conditionally in a number of places as we should, but one of them does it unconditionally. Instead, change it to call cc-disable-warning as we do elsewhere. The original patch that caused it was merged into linux-4.7, then 4.8 removed the change and 4.9 brought it back, so we probably want a backport to 4.9 once this is merged. Use a ':=' assignment instead of '=' to force the cc-disable-warning call to only be evaluated once instead of every time. Cc: stable@xxxxxxxxxxxxxxx Fixes: a76bcf557ef4 ("Kbuild: enable -Wmaybe-uninitialized warning for "make W=1"") Fixes: e72e2dfe7c16 ("gcov: disable -Wmaybe-uninitialized warning") Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> ---------------------------------------->8------------------------------------- -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html