From: Arnd Bergmann <arnd@xxxxxxxx> Combining UBSAN and GCOV in randconfig builds results in a number of stack frame size warnings, such as: crypto/twofish_common.c:683:1: error: the frame size of 2040 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] drivers/media/platform/mediatek/vcodec/vdec/vdec_vp9_req_lat_if.c:1589:1: error: the frame size of 1696 bytes is larger than 1400 bytes [-Werror=frame-larger-than=] drivers/media/platform/verisilicon/hantro_g2_vp9_dec.c:754:1: error: the frame size of 1260 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] drivers/staging/media/ipu3/ipu3-css-params.c:1206:1: error: the frame size of 1080 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] drivers/staging/media/rkvdec/rkvdec-vp9.c:1042:1: error: the frame size of 2176 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] drivers/staging/media/rkvdec/rkvdec-vp9.c:995:1: error: the frame size of 1656 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] I managed to track this down to the -fsanitize=bounds option clashing with the -fprofile-arcs option, which leads a lot of spilled temporary variables in generated instrumentation code. Hopefully this can be addressed in future gcc releases the same way that clang handles the combination, but for existing compiler releases, it seems best to disable one of the two flags. This can be done either globally by just not passing both at the same time, or locally using the no_sanitize or no_instrument_function attributes in the affected functions. Try the simplest approach here, and turn off -fsanitize=bounds on gcc when GCOV is enabled, leaving the rest of UBSAN working. Doing this globally also helps avoid inefficient code from the same problem that did not push the build over the warning limit. Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Link: https://lore.kernel.org/stable/6b1a0ee6-c78b-4873-bfd5-89798fce9899@kili.mountain/ Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110074 Link: https://godbolt.org/z/zvf7YqK5K Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> --- lib/Kconfig.ubsan | 2 ++ 1 file changed, 2 insertions(+) diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan index f7cbbad2bb2f4..8f71ff8f27576 100644 --- a/lib/Kconfig.ubsan +++ b/lib/Kconfig.ubsan @@ -29,6 +29,8 @@ config UBSAN_TRAP config CC_HAS_UBSAN_BOUNDS_STRICT def_bool $(cc-option,-fsanitize=bounds-strict) + # work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110074 + depends on GCC_VERSION > 140000 || !GCOV_PROFILE_ALL help The -fsanitize=bounds-strict option is only available on GCC, but uses the more strict handling of arrays that includes knowledge -- 2.39.2
