From: Vince Weaver <vincent.weaver@maine.edu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [perf] more perf_fuzzer memory corruption
Date: Tue, 29 Apr 2014 14:11:09 -0400 (EDT) [thread overview]
Message-ID: <alpine.DEB.2.10.1404291407180.22490@vincent-weaver-1.umelst.maine.edu> (raw)
In-Reply-To: <20140429085236.GO27561@twins.programming.kicks-ass.net>
On Tue, 29 Apr 2014, Peter Zijlstra wrote:
> On Mon, Apr 28, 2014 at 10:21:34AM -0400, Vince Weaver wrote:
> > so it's looking more and more like this issue is with a
> > PERF_COUNT_SW_TASK_CLOCK
> > event.
>
> But they don't actually use the hlist thing..
yes.
This turns out into another issue that I think is just use-after-free
memory corruption exhibiting itself a different way.
I've documented at least 8 different types of error message that I think
are all due to this issue.
> So this is a different problem from the hlist corruption?
Who knows. That's why I'm trying to get this issue fixed so I can figure
out which of the 10+ other bugs I'm tracking are the same or different.
> > This is made all the more confusing because the PERF_COUNT_SW_TASK_CLOCK
> > events are handled by their own PMU even though it's faked up so they look
> > like regular software events. Is there a reason for that?
>
> This was the easiest route when we introduced the mulitple pmu thing or
> so, its been on the todo list for a cleanup ever since :-/
It was very confusing and poorly documented, as is much of the perf_event
files. And yes, I know, I should do something about it rather than
complain.
I've actually given up on source code inspection to figure out what's
going on in kernel/events/core.c. What I do now is write simple test
cases and do an ftrace function trace. The results are often surprising.
Vince
next prev parent reply other threads:[~2014-04-29 18:07 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-15 21:37 [perf] more perf_fuzzer memory corruption Vince Weaver
2014-04-15 21:49 ` Thomas Gleixner
2014-04-16 3:21 ` Vince Weaver
2014-04-16 4:18 ` Vince Weaver
2014-04-16 14:15 ` Peter Zijlstra
2014-04-16 17:30 ` Vince Weaver
2014-04-16 17:43 ` Vince Weaver
2014-04-16 17:47 ` Peter Zijlstra
2014-04-17 9:48 ` Ingo Molnar
2014-04-17 11:45 ` Peter Zijlstra
2014-04-17 14:22 ` Ingo Molnar
2014-04-17 14:42 ` Vince Weaver
2014-04-17 14:54 ` Peter Zijlstra
2014-04-17 15:35 ` Vince Weaver
2014-04-18 14:45 ` Vince Weaver
2014-04-18 14:51 ` Vince Weaver
2014-04-18 15:23 ` Peter Zijlstra
2014-04-18 16:59 ` Peter Zijlstra
2014-04-18 17:15 ` Peter Zijlstra
2014-04-23 20:58 ` Vince Weaver
2014-04-25 2:51 ` Vince Weaver
2014-04-28 14:21 ` Vince Weaver
2014-04-28 19:38 ` Vince Weaver
2014-04-29 9:46 ` Peter Zijlstra
2014-04-29 18:21 ` Vince Weaver
2014-04-29 19:01 ` Peter Zijlstra
2014-04-29 20:59 ` Vince Weaver
2014-04-30 18:44 ` Peter Zijlstra
2014-04-30 21:08 ` Vince Weaver
2014-04-30 22:51 ` Thomas Gleixner
2014-05-01 10:26 ` Peter Zijlstra
2014-05-01 11:50 ` Peter Zijlstra
2014-05-01 12:35 ` Thomas Gleixner
2014-05-01 13:12 ` Peter Zijlstra
2014-05-01 13:29 ` Thomas Gleixner
2014-05-01 13:22 ` Vince Weaver
2014-05-01 14:07 ` Vince Weaver
2014-05-01 14:27 ` Vince Weaver
2014-05-01 15:09 ` Peter Zijlstra
2014-05-01 15:50 ` Vince Weaver
2014-05-01 16:31 ` Thomas Gleixner
2014-05-01 17:18 ` Vince Weaver
2014-05-01 18:49 ` Vince Weaver
2014-05-01 21:32 ` Vince Weaver
2014-05-02 11:15 ` Peter Zijlstra
2014-05-02 15:42 ` Peter Zijlstra
2014-05-02 16:22 ` Vince Weaver
2014-05-02 16:22 ` Peter Zijlstra
2014-05-02 16:43 ` Vince Weaver
2014-05-02 17:27 ` Peter Zijlstra
2014-05-02 17:46 ` Vince Weaver
2014-05-02 19:12 ` Thomas Gleixner
2014-05-02 20:15 ` Vince Weaver
2014-05-02 20:45 ` Thomas Gleixner
2014-05-03 2:32 ` Vince Weaver
2014-05-03 3:02 ` Vince Weaver
2014-05-03 7:33 ` Peter Zijlstra
2014-05-05 9:31 ` Peter Zijlstra
2014-05-05 16:00 ` Vince Weaver
2014-05-05 17:10 ` Vince Weaver
2014-05-05 17:14 ` Peter Zijlstra
2014-05-05 18:47 ` Vince Weaver
2014-05-05 19:36 ` Peter Zijlstra
2014-05-05 19:51 ` Vince Weaver
2014-05-06 1:06 ` Vince Weaver
2014-05-06 16:57 ` Vince Weaver
2014-05-07 16:45 ` Peter Zijlstra
2014-05-08 10:40 ` [tip:perf/core] perf: Fix perf_event_init_context() tip-bot for Peter Zijlstra
2014-05-05 17:29 ` [perf] more perf_fuzzer memory corruption Ingo Molnar
2014-05-06 4:51 ` Vince Weaver
2014-05-06 17:06 ` Vince Weaver
2014-05-07 19:12 ` Ingo Molnar
2014-05-07 19:11 ` Ingo Molnar
2014-05-08 10:40 ` [tip:perf/core] perf: Fix race in removing an event tip-bot for Peter Zijlstra
2014-05-02 17:06 ` [perf] more perf_fuzzer memory corruption Vince Weaver
2014-05-02 17:04 ` Peter Zijlstra
2014-04-29 19:26 ` Steven Rostedt
2014-04-29 8:52 ` Peter Zijlstra
2014-04-29 18:11 ` Vince Weaver [this message]
2014-04-29 19:21 ` Steven Rostedt
2014-04-28 17:48 ` Thomas Gleixner
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