Hi David, On Thu, Jun 06, 2019 at 10:43:33AM +0100, David Howells wrote: [..] > diff --git a/samples/watch_queue/Makefile b/samples/watch_queue/Makefile > new file mode 100644 > index 000000000000..42b694430d0f > --- /dev/null > +++ b/samples/watch_queue/Makefile > @@ -0,0 +1,9 @@ > +# List of programs to build > +hostprogs-y := watch_test > + > +# Tell kbuild to always build the programs > +always := $(hostprogs-y) > + > +HOSTCFLAGS_watch_test.o += -I$(objtree)/usr/include How about arm64? Do you intend to enable cross-compilation? > + > +HOSTLOADLIBES_watch_test += -lkeyutils > diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c > new file mode 100644 > index 000000000000..893a5380f792 > --- /dev/null > +++ b/samples/watch_queue/watch_test.c [..] > + asm ("lfence" : : : "memory" ); [..] > + asm("mfence" ::: "memory"); FWIW, trying to cross-compile it returned: aarch64-linux-gnu-gcc -I../../usr/include -I../../include watch_test.c -o watch_test /tmp/ccDXYynm.s: Assembler messages: /tmp/ccDXYynm.s:471: Error: unknown mnemonic `lfence' -- `lfence' /tmp/ccDXYynm.s:568: Error: unknown mnemonic `mfence' -- `mfence' <builtin>: recipe for target 'watch_test' failed make: *** [watch_test] Error 1 -- Best Regards, Eugeniu.