Process of analyzing events caused by 2 functions: mmap_read() and
finished_round().
During mmap_read(), perf receives events from shared memory, queues
their pointers for further processing in finished_round() and notifies
the kernel that the events have been processed.
By the time when finished_round() is invoked, queued events can be
overwritten by the kernel, so the finished_round() occurs on potentially
corrupted memory.

Let's copy events when queueing.

Signed-off-by: Alexander Yarygin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
---
 tools/perf/builtin-kvm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index f5d3ae4..c5b6d1d 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -1369,6 +1369,7 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
                goto out;
        }
        kvm->session->evlist = kvm->evlist;
+       kvm->session->copy_on_queue = true;
        perf_session__set_id_hdr_size(kvm->session);
        machine__synthesize_threads(&kvm->session->machines.host, 
&kvm->opts.target,
                                    kvm->evlist->threads, false);
-- 
1.9.1

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