-Wimplicit-fallthrough=5 was under cc-option because it was only available in GCC 7.x and newer so the build is now broken for GCC 5.x and 6.x: gcc: error: unrecognized command line option '-Wimplicit-fallthrough=5'; did you mean '-Wno-fallthrough'? Fix this by moving -Wimplicit-fallthrough=5 under cc-option. Fixes: dee2b702bcf0 ("kconfig: Add support for -Wimplicit-fallthrough") Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx> Co-developed-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> --- Changes in v3: - Keep the original CC_IS_GCC part of the test[1]. Link: https://lore.kernel.org/linux-hardening/CAHk-=whaJCEwqKbekSNjziY4RMTKzkRkkrOM4MEZQEo0j3HT=Q@xxxxxxxxxxxxxx/ [1] Changes in v2: - Add Fixes tag. init/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/init/Kconfig b/init/Kconfig index 036b750e8d8a..4b7bac10c72d 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -887,7 +887,7 @@ config CC_HAS_INT128 config CC_IMPLICIT_FALLTHROUGH string - default "-Wimplicit-fallthrough=5" if CC_IS_GCC + default "-Wimplicit-fallthrough=5" if CC_IS_GCC && $(cc-option,-Wimplicit-fallthrough=5) default "-Wimplicit-fallthrough" if CC_IS_CLANG && $(cc-option,-Wunreachable-code-fallthrough) # -- 2.27.0