Em Thu, Nov 19, 2015 at 10:29:07AM +0800, Wangnan (F) escreveu: > On 2015/11/19 10:21, Wangnan (F) wrote: > >On 2015/11/19 9:24, Wangnan (F) wrote: > >>On 2015/11/19 6:44, Arnaldo Carvalho de Melo wrote: > >>>Have you guys ever saw this? > >>> > >>>[acme@zoo linux]$ alias m > >>>alias m='perf stat -e cycles make O=/tmp/build/perf -C tools/perf > >>>install-bin' > >>>[acme @zoo linux]$ m > >>>make: Entering directory '/home/git/linux/tools/perf' > >>> BUILD: Doing 'make -j4' parallel build > >>>make[2]: Nothing to be done for 'fixdep'. > >>> CC /tmp/build/perf/util/machine.o > >>> LD /tmp/build/perf/util/libperf-in.o > >>>No libelf found > >>>BPF API too old > >> > >>This error message means the kernel header in rootfs is too old, > >>causes tools/build/feature/test-bpf.c failed to be built. > > > >Strange... even in feature detection it should check BPF API through > >kernel source where you are using to build perf... > > > >I guess you are not using NFS or share it with other people?
Some build problem just happened and your question came to my mind, yeah, sometimes I NFS mount it from a RHEL6 (and other distros) to do 'make -C tools/perf build-test' to check it works with those distros, and I forgot to do a: make -C tools/ clean I guess I'll have to try to make build-test support O=... So that polluting the source tree doesn't causes problems like this. Will try even to make it turn the source tree read only so that we spot when O= is not being honoured... - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
