On Fri, Jan 12, 2018 at 4:57 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote: > > * Andy Lutomirski <luto@xxxxxxxxxx> wrote: > >> tools/testing/selftests/x86/Makefile | 2 +- >> tools/testing/selftests/x86/test_vsyscall.c | 500 ++++++++++++++++++++++++++++ >> 2 files changed, 501 insertions(+), 1 deletion(-) >> create mode 100644 tools/testing/selftests/x86/test_vsyscall.c > > Hm, it doesn't even build here, on Ubuntu latest (Artful): > > triton:~/tip/tools/testing/selftests/x86> make test_vsyscall > gcc -O2 -g -std=gnu99 -pthread -Wall -no-pie test_vsyscall.c -o test_vsyscall > /tmp/ccKyelfb.o: In function `init_vdso': > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:68: undefined reference to `dlopen' > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:76: undefined reference to `dlsym' > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:80: undefined reference to `dlsym' > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:84: undefined reference to `dlsym' > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:88: undefined reference to `dlsym' > /home/mingo/tip/tools/testing/selftests/x86/test_vsyscall.c:70: undefined reference to `dlopen' > collect2: error: ld returned 1 exit status > <builtin>: recipe for target 'test_vsyscall' failed > make: *** [test_vsyscall] Error 1 > You're not supposed to do that :) The targets are test_vsyscall_32 and test_vsyscall_64 or just plain make. I think you're just ending up with make's default rule to try to build it and it's not working. We could try adding something like: # The x86 selftests have files like foo.c that don't produce binaries # called foo (they're foo_32 and foo_64 instead). Prevent confusion # if someone types 'make foo'. % : %.c % : %.o to tools/testing/selftests/x86/Makefile, but that's a bit gross.