Some distributions (such as Ubuntu) configure GCC so that _FORTIFY_SOURCE is automatically enabled at -O1 or above. This results in some fortified version of definitions of standard library functions are included. While linker resolves the symbols, the fortified versions might override the definitions in lib/string_override.c and reference to those PLT entries in GLIBC. This is not a problem for the code in host, but it is a disaster for the guest code. E.g., if build and run x86/nested_emulation_test on Ubuntu 24.04 will encounter a L1 #PF due to memset() reference to __memset_chk@plt. The option -fno-builtin-memset is not helpful here, because those fortified versions are not built-in but some definitions which are included by header, they are for different intentions. In order to eliminate the unpredictable behaviors may vary depending on the linker and platform, add the "-U_FORTIFY_SOURCE" into CFLAGS to prevent from introducing the fortified definitions. Signed-off-by: Zhiquan Li --- tools/testing/selftests/kvm/Makefile.kvm | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index ba5c2b643efa..d45bf4ccb3bf 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -251,6 +251,7 @@ LINUX_TOOL_INCLUDE = $(top_srcdir)/tools/include LINUX_TOOL_ARCH_INCLUDE = $(top_srcdir)/tools/arch/$(ARCH)/include CFLAGS += -Wall -Wstrict-prototypes -Wuninitialized -O2 -g -std=gnu99 \ -Wno-gnu-variable-sized-type-not-at-end -MD -MP -DCONFIG_64BIT \ + -U_FORTIFY_SOURCE \ -fno-builtin-memcmp -fno-builtin-memcpy \ -fno-builtin-memset -fno-builtin-strnlen \ -fno-stack-protector -fno-PIE -fno-strict-aliasing \ -- 2.43.0