Em Fri, Aug 07, 2020 at 09:08:24AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, Aug 06, 2020 at 09:43:57PM +0200, Jiri Olsa escreveu: > > On Wed, Aug 05, 2020 at 10:29:37AM +0800, Jin Yao wrote: > > > We received an error report that perf-record caused 'Segmentation fault' > > > on a newly system (e.g. on the new installed ubuntu). > > > > > > (gdb) backtrace > > > #0 __read_once_size (size=4, res=<synthetic pointer>, p=0x14) at > > > /root/0-jinyao/acme/tools/include/linux/compiler.h:139 > > > #1 atomic_read (v=0x14) at > > > /root/0-jinyao/acme/tools/include/asm/../../arch/x86/include/asm/atomic.h:28 > > > #2 refcount_read (r=0x14) at > > > /root/0-jinyao/acme/tools/include/linux/refcount.h:65 > > > #3 perf_mmap__read_init (map=map@entry=0x0) at mmap.c:177 > > > #4 0x0000561ce5c0de39 in perf_evlist__poll_thread (arg=0x561ce68584d0) > > > at util/sideband_evlist.c:62 > > > #5 0x00007fad78491609 in start_thread (arg=<optimized out>) at > > > pthread_create.c:477 > > > #6 0x00007fad7823c103 in clone () at > > > ../sysdeps/unix/sysv/linux/x86_64/clone.S:95 > > > > hum, I recall discussing the same issue, > > I thought it was already fixed :-\ in any case: > > > > Acked-by: Jiri Olsa <[email protected]> > > I added this: > > Fixes: 23cbb41c939a ("perf record: Move side band evlist setup to separate > routine") > > To help this fixe go back to a few stable kernels. Technically the > problem was introduced much earlier, when the side band thread was > added, but then this would require more cherry-picking of patches and > since we have a workaround, i.e. build with libbpf, I think this is > enough.
I backtrack on that, as the sideband event is not just for BPF... The switch-output-event code uses it as well, so it can't be dependent on LIBBPF being built... I'll see what I can do - Arnaldo
