Messages in this thread Patch in this message | | | Date | Fri, 7 Aug 2020 09:16:29 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf record: Skip side-band event setup if HAVE_LIBBPF_SUPPORT is not set |
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Em Fri, Aug 07, 2020 at 09:09:56AM -0300, Arnaldo Carvalho de Melo escreveu: > 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 <jolsa@redhat.com> > > > > 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
So this is the change I made, the side band thread is may have been already created by
[acme@quaco ~]$ perf record -h switch-output-event
Usage: perf record [<options>] [<command>] or: perf record [<options>] -- <command> [<options>]
--switch-output-event <switch output event> switch output event selector. use 'perf list' to list available events
[acme@quaco ~]$
I'm doing some extra checking now on your report, and the patch below has skews because it clashed with the clockid patches by Jiri so I had to resolve its merge.
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 7d97c8e9f7f9..c12b5b072519 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1511,6 +1511,7 @@ static int record__synthesize(struct record *rec, bool tail) return err; } +#ifdef HAVE_LIBBPF_SUPPORT static int record__process_signal_event(union perf_event *event __maybe_unused, void *data) { struct record *rec = data; @@ -1592,6 +1593,12 @@ static int record__init_clock(struct record *rec) session->header.env.clock.clockid_ns = ref; return 0; } +#else +static int record__setup_sb_evlist(struct record *rec __maybe_unused) +{ + return 0; +} +#endif static int __cmd_record(struct record *rec, int argc, const char **argv) {
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