Note there is a bug raised by H.J. Liu : Bug 199129: Don't build vDSO with $(RETPOLINE_CFLAGS) -DRETPOLINE (https://bugzilla.kernel.org/show_bug.cgi?id=199129)
If you agree it is a bug, then use both patches from post : '[PATCH v4.16-rc5 (2)] x86/vdso: VDSO should handle \ clock_gettime(CLOCK_MONOTONIC_RAW) without syscall ' else, use the single patch from $subject, which makes the calls to the statics in vclock_gettime.c' use indirect_branch("keep") / function_return("keep") , to avoid generation of thunk relocations which would not occur unless compiled with -mindirect-branch=thunk-extern -mindirect-branch-register . Thanks & Regards, Jason