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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:17:41 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 23:17:41 +0300
commit6e8d666e925333c55378e8d5540a8a9ee0eea9c5 (patch)
tree68776cc543e97cda5bd003237fd2aa4cad585602
parent468fc7ed5537615efe671d94248446ac24679773 (diff)
downloadlinux-6e8d666e925333c55378e8d5540a8a9ee0eea9c5.tar.xz
Disable "maybe-uninitialized" warning globally
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>
-rw-r--r--Makefile7
-rw-r--r--arch/arc/Makefile4
-rw-r--r--scripts/Makefile.ubsan4
3 files changed, 5 insertions, 10 deletions
diff --git a/Makefile b/Makefile
index 776b6a3c40f1..d384848478b9 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
CFLAGS_KCOV = -fsanitize-coverage=trace-pc
@@ -619,12 +619,13 @@ 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
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 85814e74677d..601ed173080b 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -74,9 +74,7 @@ endif
ifndef CONFIG_CC_OPTIMIZE_FOR_SIZE
# Generic build system uses -O2, we want -O3
# Note: No need to add to cflags-y as that happens anyways
-#
-# Disable the false maybe-uninitialized warings gcc spits out at -O3
-ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,)
+ARCH_CFLAGS += -O3
endif
# small data is default for elf32 tool-chain. If not usable, disable it
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index 77ce538268b5..8ab68679cfb5 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -14,8 +14,4 @@ ifdef CONFIG_UBSAN
ifdef CONFIG_UBSAN_ALIGNMENT
CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
endif
-
- # -fsanitize=* options makes GCC less smart than usual and
- # increase number of 'maybe-uninitialized false-positives
- CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized)
endif