On Thu, 4 Dec 2025 08:17:20 -0800 Guenter Roeck wrote:
-CFLAGS += $(KHDR_INCLUDES) -Wall -Wflex-array-member-not-at-end +CFLAGS += $(KHDR_INCLUDES) -Wall $(call cc-option,-Wflex-array-member-not-at-end)
Hm, the Claude code review we have hooked up to patchwork says:
Is cc-option available in the selftest build environment? Looking at tools/testing/selftests/lib.mk (included at line 14), it doesn't include scripts/Makefile.compiler where cc-option is defined. When cc-option is undefined, $(call cc-option,...) expands to an empty string, which means the -Wflex-array-member-not-at-end flag won't be added even on compilers that support it.
This defeats the purpose of commit 1838731f1072c which added the warning flag to catch flexible array issues.
For comparison, tools/testing/selftests/nolibc/Makefile explicitly includes scripts/Makefile.compiler before using cc-option.
Testing it:
$ make -C tools/testing/selftests/ TARGETS=net/af_unix Q= V=1 make: Entering directory '/home/kicinski/devel/linux/tools/testing/selftests' make[1]: Entering directory '/home/kicinski/devel/linux/tools/testing/selftests/net/af_unix' gcc -isystem /home/kicinski/devel/linux/usr/include -Wall -D_GNU_SOURCE= diag_uid.c -o /home/kicinski/devel/linux/tools/testing/selftests/net/af_unix/diag_uid
looks like the flag just disappears. Even tho:
gcc version 15.2.1