linux-kernel - [PATCH 31/36] Revert "perf sched: Handle PERF_RECORD

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Date:	Thu, 28 Mar 2013 14:02:31 -0300
From:	Arnaldo Carvalho de Melo <acme@...radead.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>, Mike Galbraith <efault@....de>,
	Namhyung Kim <namhyung@...il.com>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>
Subject: [PATCH 31/36] Revert "perf sched: Handle PERF_RECORD_EXIT events"

From: Arnaldo Carvalho de Melo <acme@...hat.com>

This reverts commit 0439539f72ea222fbfe511b47318b9c1815a7108.

This caused this segfault:

[root@...dy linux]# perf sched rec
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 1.306 MB perf.data (~57062 samples) ]
perf
[root@...dy linux]# perf sched lat
perf: builtin-sched.c:781: thread_atoms_search: Assertion `!(thread != atoms->thread)' failed.
Aborted (core dumped)
[root@...dy linux]#

Further investigation is needed to check that even with machine__remove_thread()
not really deleting the thread referenced in the PERF_RECORD_EXIT (it goes to
machine->dead_threads, because references may still exist to them in things like
 hist, etc) some event later comes for this dead thread and then
machine__findnew_thread() will create a new thead instance that will not be the
same as the one referenced by work_atoms->thread in thread_atoms_search().

For now just revert this patch to get the 'perf sched lat' back working.

Cc: David Ahern <dsahern@...il.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Mike Galbraith <efault@....de>
Cc: Namhyung Kim <namhyung@...il.com>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
echo Link: http://lkml.kernel.org/n/tip-`ranpwd -l 24`@....kernel.org
Link: http://lkml.kernel.org/n/tip-hg4s6e5txiwqe00h8rdg1sin@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-sched.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 1382294..2da2a6c 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -1671,7 +1671,6 @@ int cmd_sched(int argc, const char **argv, const char *prefix __maybe_unused)
 			.sample		 = perf_sched__process_tracepoint_sample,
 			.comm		 = perf_event__process_comm,
 			.lost		 = perf_event__process_lost,
-			.exit		 = perf_event__process_exit,
 			.fork		 = perf_event__process_fork,
 			.ordered_samples = true,
 		},
-- 
1.7.1

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