Re: [PATCH] Kbuild: use cc-disable-warning consistently for maybe-uninitialized
From: Arnd Bergmann
Date: Fri Jan 27 2017 - 11:09:24 EST
On Fri, Jan 13, 2017 at 4:40 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> 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>
any plans to pick this up for v4.10?
> Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/Makefile b/Makefile
> index 4fcc0f2dd93c..dbe9ce5d0e96 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -370,7 +370,7 @@ LDFLAGS_MODULE =
> CFLAGS_KERNEL =
> AFLAGS_KERNEL =
> LDFLAGS_vmlinux =
> -CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized
> +CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im $(call cc-disable-warning,maybe-uninitialized,)
> CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,)