4 files changed, 16 insertions, 5 deletions

diff --git a/Makefile b/Makefile
index f97f786de58d..06e2b73978e8 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
+CFLAGS_GCOV     = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized
 CFLAGS_KCOV     := $(call cc-option,-fsanitize-coverage=trace-pc,)
 
 
@@ -620,7 +620,6 @@ ARCH_CFLAGS :=
 include arch/$(SRCARCH)/Makefile
 
 KBUILD_CFLAGS   += $(call cc-option,-fno-delete-null-pointer-checks,)
-KBUILD_CFLAGS   += $(call cc-disable-warning,maybe-uninitialized,)
 KBUILD_CFLAGS   += $(call cc-disable-warning,frame-address,)
 
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
@@ -629,15 +628,18 @@ KBUILD_CFLAGS	+= $(call cc-option,-fdata-sections,)
 endif
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS   += -Os
+KBUILD_CFLAGS   += -Os $(call cc-disable-warning,maybe-uninitialized,)
 else
 ifdef CONFIG_PROFILE_ALL_BRANCHES
-KBUILD_CFLAGS   += -O2
+KBUILD_CFLAGS   += -O2 $(call cc-disable-warning,maybe-uninitialized,)
 else
 KBUILD_CFLAGS   += -O2
 endif
 endif
 
+KBUILD_CFLAGS += $(call cc-ifversion, -lt, 0409, \
+                        $(call cc-disable-warning,maybe-uninitialized,))
+
 # Tell gcc to never replace conditional load with a non-conditional one
 KBUILD_CFLAGS   += $(call cc-option,--param=allow-store-data-races=0)
 
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index 864adad52280..25f81a1db9f9 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -68,7 +68,9 @@ cflags-$(CONFIG_ARC_DW2_UNWIND)		+= -fasynchronous-unwind-tables $(cfi)
 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
-ARCH_CFLAGS += -O3
+#
+# Disable the false maybe-uninitialized warings gcc spits out at -O3
+ARCH_CFLAGS += -O3 $(call cc-disable-warning,maybe-uninitialized,)
 endif
 
 # small data is default for elf32 tool-chain. If not usable, disable it
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index 53449a6ff6aa..7fc2c5a3dbbe 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -36,6 +36,7 @@ warning-2 += -Wshadow
 warning-2 += $(call cc-option, -Wlogical-op)
 warning-2 += $(call cc-option, -Wmissing-field-initializers)
 warning-2 += $(call cc-option, -Wsign-compare)
+warning-2 += $(call cc-option, -Wmaybe-uninitialized)
 
 warning-3 := -Wbad-function-cast
 warning-3 += -Wcast-qual
@@ -59,6 +60,8 @@ endif
 KBUILD_CFLAGS += $(warning)
 else
 
+KBUILD_CFLAGS += $(call cc-disable-warning, maybe-uninitialized)
+
 ifeq ($(cc-name),clang)
 KBUILD_CFLAGS += $(call cc-disable-warning, initializer-overrides)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-value)
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index dd779c40c8e6..3b1b13818d59 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -17,4 +17,8 @@ endif
 ifdef CONFIG_UBSAN_NULL
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=null)
 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