[PATCH 4.4 20/73] gcov: disable -Wmaybe-uninitialized warning

From: Greg Kroah-Hartman
Date: Wed Sep 28 2016 - 05:07:49 EST

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


From: Arnd Bergmann <arnd@xxxxxxxx>

commit e72e2dfe7c16ffbfbabf9cb24adc6d9f93a4fe37 upstream.

When gcov profiling is enabled, we see a lot of spurious warnings about
possibly uninitialized variables being used:

arch/arm/mm/dma-mapping.c: In function 'arm_coherent_iommu_map_page':
arch/arm/mm/dma-mapping.c:1085:16: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/clk/st/clk-flexgen.c: In function 'st_of_flexgen_setup':
drivers/clk/st/clk-flexgen.c:323:9: warning: 'num_parents' may be used uninitialized in this function [-Wmaybe-uninitialized]
kernel/cgroup.c: In function 'cgroup_mount':
kernel/cgroup.c:2119:11: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized]

All of these are false positives, so it seems better to just disable
the warnings whenever GCOV is enabled. Most users don't enable GCOV,
and based on a prior patch, it is now also disabled for 'allmodconfig'
builds, so there should be no downsides of doing this.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Peter Oberparleiter <oberpar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michal Marek <mmarek@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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

# Use USERINCLUDE when you must reference the UAPI directories only.