Since we link purgatory.ro with -r aka we enable "incremental linking" no checks for unresolved symbols is done while linking purgatory.ro.
Changes to the sha256 code has caused the purgatory in 5.4-rc1 to have a missing symbol on memzero_explicit, yet things still happily build. This commit adds an extra check for unresolved symbols by calling ld without -r before running bin2c to generate kexec-purgatory.c. This causes a build of 5.4-rc1 with this patch added to fail as it should: CHK arch/x86/purgatory/purgatory.ro ld: arch/x86/purgatory/purgatory.ro: in function `sha256_transform': sha256.c:(.text+0x1c0c): undefined reference to `memzero_explicit' make[2]: *** [arch/x86/purgatory/Makefile:72: arch/x86/purgatory/kexec-purgatory.c] Error 1 make[1]: *** [scripts/Makefile.build:509: arch/x86/purgatory] Error 2 make: *** [Makefile:1650: arch/x86] Error 2 This will help us catch missing symbols in the purgatory sooner. Note this commit also removes --no-undefined from LDFLAGS_purgatory.ro as that has no effect. Signed-off-by: Hans de Goede <hdego...@redhat.com> --- arch/x86/purgatory/Makefile | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index fb4ee5444379..0da0794ef1f0 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -14,7 +14,7 @@ $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE CFLAGS_sha256.o := -D__DISABLE_EXPORTS -LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib +LDFLAGS_purgatory.ro := -e purgatory_start -r -nostdlib -z nodefaultlib targets += purgatory.ro KASAN_SANITIZE := n @@ -60,10 +60,16 @@ $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE targets += kexec-purgatory.c +# Since we link purgatory.ro with -r unresolved symbols are not checked, +# so we check this before generating kexec-purgatory.c instead +quiet_cmd_check_purgatory = CHK $< + cmd_check_purgatory = ld -e purgatory_start $< + quiet_cmd_bin2c = BIN2C $@ cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@ $(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE + $(call if_changed,check_purgatory) $(call if_changed,bin2c) obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o -- 2.23.0