[PATCH 3.12 11/84] Disable "maybe-uninitialized" warning globally

From: Jiri Slaby
Date: Mon Oct 17 2016 - 04:21:39 EST


From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

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@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
Makefile | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index c0e575c2594c..39bfb82f7106 100644
--- a/Makefile
+++ b/Makefile
@@ -351,7 +351,7 @@ 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.
@@ -582,11 +582,13 @@ endif # $(dot-config)
# Defaults to vmlinux, but the arch makefile usually adds further targets
all: vmlinux

+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
--
2.10.1