path: root/Makefile
diff options
authorArnd Bergmann <>2016-04-25 17:35:30 +0200
committerMichal Marek <>2016-05-10 17:12:50 +0200
commitc87bf431448b404a6ef5fbabd74c0e3e42157a7f (patch)
tree48e086035b97b593b9bf4728ab7bc12b27588656 /Makefile
parentcc622420798c4bcf093785d872525087a7798db9 (diff)
gcov: disable tree-loop-im to reduce stack usage
Enabling CONFIG_GCOV_PROFILE_ALL produces us a lot of warnings like lib/lz4/lz4hc_compress.c: In function 'lz4_compresshcctx': lib/lz4/lz4hc_compress.c:514:1: warning: the frame size of 1504 bytes is larger than 1024 bytes [-Wframe-larger-than=] After some investigation, I found that this behavior started with gcc-4.9, and opened A suggested workaround for it is to use the -fno-tree-loop-im flag that turns off one of the optimization stages in gcc, so the code runs a little slower but does not use excessive amounts of stack. We could make this conditional on the gcc version, but I could not find an easy way to do this in Kbuild and the benefit would be fairly small, given that most of the gcc version in production are affected now. I'm marking this for 'stable' backports because it addresses a bug with code generation in gcc that exists in all kernel versions with the affected gcc releases. Signed-off-by: Arnd Bergmann <> Acked-by: Peter Oberparleiter <> Cc: Signed-off-by: Michal Marek <>
Diffstat (limited to 'Makefile')
1 files changed, 1 insertions, 1 deletions
diff --git a/Makefile b/Makefile
index ffeb6d9e17bb..0b93a298c393 100644
--- a/Makefile
+++ b/Makefile
@@ -368,7 +368,7 @@ AFLAGS_MODULE =
-CFLAGS_GCOV = -fprofile-arcs -ftest-coverage
+CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im
CFLAGS_KCOV = -fsanitize-coverage=trace-pc