On Tue, Jun 25, 2024 at 2:00 AM Jan Beulich <jbeul...@suse.com> wrote: > > On 24.06.2024 23:23, Tamas K Lengyel wrote: > > On Mon, Jun 24, 2024 at 11:55 AM Jan Beulich <jbeul...@suse.com> wrote: > >> > >> On 21.06.2024 21:14, Tamas K Lengyel wrote: > >>> @@ -58,6 +58,9 @@ afl-harness: afl-harness.o $(OBJS) cpuid.o wrappers.o > >>> afl-harness-cov: afl-harness-cov.o $(patsubst %.o,%-cov.o,$(OBJS)) > >>> cpuid.o wrappers.o > >>> $(CC) $(CFLAGS) $(GCOV_FLAGS) $(addprefix > >>> -Wl$(comma)--wrap=,$(WRAPPED)) $^ -o $@ > >>> > >>> +libfuzzer-harness: $(OBJS) cpuid.o > >>> + $(CC) $(CFLAGS) $(LIB_FUZZING_ENGINE) -fsanitize=fuzzer $^ -o $@ > >> > >> What is LIB_FUZZING_ENGINE? I don't think we have any use of that in the > >> tree anywhere. > > > > It's used by oss-fuzz, otherwise it's not doing anything. > > > >> > >> I'm further surprised you get away here without wrappers.o. > > > > Wrappers.o was actually breaking the build for oss-fuzz at the linking > > stage. It works just fine without it. > > I'm worried here, to be honest. The wrappers serve a pretty important > role, and I'm having a hard time seeing why they shouldn't be needed > here when they're needed both for the test and afl harnesses. Could > you add some more detail on the build issues you encountered?
With wrappers.o included doing the build in the oss-fuzz docker (ubuntu 20.04 base) fails with: ... clang -O1 -fno-omit-frame-pointer -gline-tables-only -Wno-error=enum-constexpr-conversion -Wno-error=incompatible-function-pointer-types -Wno-error=int-conversion -Wno-error=deprecated-declarations -Wno-error=implicit-function-declaration -Wno-error=implicit-int -DFUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -fsanitize=address -fsanitize-address-use-after-scope -fsanitize=fuzzer-no-link -m64 -DBUILD_ID -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes -Wno-unused-but-set-variable -Wno-unused-local-typedefs -g3 -Werror -Og -fno-omit-frame-pointer -D__XEN_INTERFACE_VERSION__=__XEN_LATEST_INTERFACE_VERSION__ -MMD -MP -MF .libfuzzer-harness.d -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -I/src/xen/tools/fuzz/x86_instruction_emulator/../../../tools/include -D__XEN_TOOLS__ -iquote . -fsanitize=fuzzer -fsanitize=fuzzer -Wl,--wrap=fwrite -Wl,--wrap=memcmp -Wl,--wrap=memcpy -Wl,--wrap=memset -Wl,--wrap=printf -Wl,--wrap=putchar -Wl,--wrap=puts -Wl,--wrap=snprintf -Wl,--wrap=strstr -Wl,--wrap=vprintf -Wl,--wrap=vsnprintf fuzz-emul.o x86-emulate.o x86_emulate/0f01.o x86_emulate/0fae.o x86_emulate/0fc7.o x86_emulate/decode.o x86_emulate/fpu.o cpuid.o wrappers.o -o libfuzzer-harness /usr/bin/ld: /usr/bin/ld: DWARF error: invalid or unhandled FORM value: 0x25 /usr/local/lib/clang/18/lib/x86_64-unknown-linux-gnu/libclang_rt.fuzzer.a(fuzzer.o): in function `std::__Fuzzer::__libcpp_snprintf_l(char*, unsigned long, __locale_struct*, char const*, ...)': cxa_noexception.cpp:(.text._ZNSt8__Fuzzer19__libcpp_snprintf_lEPcmP15__locale_structPKcz[_ZNSt8__Fuzzer19__libcpp_snprintf_lEPcmP15__locale_structPKcz]+0x9a): undefined reference to `__wrap_vsnprintf' clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Makefile:62: libfuzzer-harness] Error 1 rm x86-emulate.c wrappers.c cpuid.c make: Leaving directory '/src/xen/tools/fuzz/x86_instruction_emulator' ERROR:__main__:Building fuzzers failed.
