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From: Nathan Chancellor <natechancellor@gmail.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	linux-kernel@vger.kernel.org,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH] drm/i915: Disable -Wuninitialized for intel_breadcrumbs.o
Date: Thu, 25 Oct 2018 12:36:01 -0700	[thread overview]
Message-ID: <20181025193601.11746-1-natechancellor@gmail.com> (raw)

This warning is disabled by default in scripts/Makefile.extrawarn when
W= is not provided but this Makefile adds -Wall after this warning is
disabled so it shows up in the build when it shouldn't:

In file included from drivers/gpu/drm/i915/intel_breadcrumbs.c:895:
drivers/gpu/drm/i915/selftests/intel_breadcrumbs.c:350:34: error:
variable 'wq' is uninitialized when used within its own initialization
[-Werror,-Wuninitialized]
        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
                                        ^~
./include/linux/wait.h:74:63: note: expanded from macro
'DECLARE_WAIT_QUEUE_HEAD_ONSTACK'
        struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
                               ~~~~                                  ^~~~
./include/linux/wait.h:72:33: note: expanded from macro
'__WAIT_QUEUE_HEAD_INIT_ONSTACK'
        ({ init_waitqueue_head(&name); name; })
                                       ^~~~
1 error generated.

This warning looks to be a false positive given that init_waitqueue_head
initializes name before it is used. Rather than disable the warning for
the full folder like commit 46e2068081e9 ("drm/i915: Disable some extra
clang warnings"), just disable it for the one problematic file because
it could be a useful warning for other cases.

Link: https://github.com/ClangBuiltLinux/linux/issues/220
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/gpu/drm/i915/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 1c2857f13ad4..f36c420afb99 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -26,6 +26,7 @@ subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
 
 # Fine grained warnings disable
 CFLAGS_i915_pci.o = $(call cc-disable-warning, override-init)
+CFLAGS_intel_breadcrumbs.o = $(call cc-disable-warning, uninitialized)
 CFLAGS_intel_fbdev.o = $(call cc-disable-warning, override-init)
 
 subdir-ccflags-y += \
-- 
2.19.1


             reply	other threads:[~2018-10-25 19:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-25 19:36 Nathan Chancellor [this message]
2018-10-25 22:20 ` Nick Desaulniers
2018-12-18 11:53   ` Chris Wilson
2018-12-18 19:01     ` Nathan Chancellor
2018-12-18 19:43       ` Nick Desaulniers
2018-12-17 17:41 ` Nathan Chancellor

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