[PATCH 4.4 21/73] Disable "maybe-uninitialized" warning globally

Greg Kroah-Hartman
2016-09-28T09:08:07Z

From: Linus Torvalds <torvalds@linux-foundation.org>

commit 6e8d666e925333c55378e8d5540a8a9ee0eea9c5 upstream.

Several build configurations had already disabled this warning because
it generates a lot of false positives. But some had not, and it was
still enabled for "allmodconfig" builds, for example.

Looking at the warnings produced, every single one I looked at was a
false positive, and the warnings are frequent enough (and big enough)
that they can easily hide real problems that you don't notice in the
noise generated by -Wmaybe-uninitialized.

The warning is good in theory, but this is a classic case of a warning
that causes more problems than the warning can solve.

If gcc gets better at avoiding false positives, we may be able to
re-enable this warning. But as is, we're better off without it, and I
want to be able to see the *real* warnings.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
Makefile | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/Makefile
+++ b/Makefile
@@ -368,7 +368,7 @@ AFLAGS_MODULE =
LDFLAGS_MODULE =
CFLAGS_KERNEL =
AFLAGS_KERNEL =
-CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized
+CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im

# Use USERINCLUDE when you must reference the UAPI directories only.
@@ -616,12 +616,13 @@ ARCH_CFLAGS :=
include arch/$(SRCARCH)/Makefile

KBUILD_CFLAGS += $(call cc-option,-fno-delete-null-pointer-checks,)
+KBUILD_CFLAGS += $(call cc-disable-warning,maybe-uninitialized,)

ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS += -Os $(call cc-disable-warning,maybe-uninitialized,)
+KBUILD_CFLAGS += -Os
else
ifdef CONFIG_PROFILE_ALL_BRANCHES
-KBUILD_CFLAGS += -O2 $(call cc-disable-warning,maybe-uninitialized,)
+KBUILD_CFLAGS += -O2
else
KBUILD_CFLAGS += -O2
endif