From: David Ahern Date: Tue, 5 Feb 2013 21:12:42 +0000 (-0700) Subject: perf evlist: Make event_copy local to mmaps X-Git-Tag: v3.9-rc1~173^2~3^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0479b8b9cf4377df5d2c81506ce93326c31eff40;p=pandora-kernel.git perf evlist: Make event_copy local to mmaps I am getting segfaults *after* the time sorting of perf samples where the event type is off the charts: (gdb) bt \#0 0x0807b1b2 in hists__inc_nr_events (hists=0x80a99c4, type=1163281902) at util/hist.c:1225 \#1 0x08070795 in perf_session_deliver_event (session=0x80a9b90, event=0xf7a6aff8, sample=0xffffc318, tool=0xffffc520, file_offset=0) at util/session.c:884 \#2 0x0806f9b9 in flush_sample_queue (s=0x80a9b90, tool=0xffffc520) at util/session.c:555 \#3 0x0806fc53 in process_finished_round (tool=0xffffc520, event=0x0, session=0x80a9b90) at util/session.c:645 This is bizarre because the event has already been processed once -- before it was added to the samples queue -- and the event was found to be sane at that time. There seem to be 2 causes: 1. perf_evlist__mmap_read updates the read location even though there are outstanding references to events sitting in the mmap buffers via the ordered samples queue. 2. There is a single evlist->event_copy for all evlist entries. event_copy is used to handle an event wrapping at the mmap buffer boundary. This patch addresses the second problem - making event_copy local to each perf_mmap. With this change my highly repeatable use case no longer fails. The first problem is much more complicated and will be the subject of a future patch. Signed-off-by: David Ahern Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1360098762-61827-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- Reading git-diff-tree failed