From: Peter Zijlstra <peterz@infradead.org>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
"Ni, BaoleX" <baolex.ni@intel.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"acme@kernel.org" <acme@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"alexander.shishkin@linux.intel.com"
<alexander.shishkin@linux.intel.com>,
"Liu, Chuansheng" <chuansheng.liu@intel.com>,
Jiri Olsa <jolsa@kernel.org>
Subject: Re: hit a KASan bug related to Perf during stress test
Date: Mon, 24 Oct 2016 14:12:02 +0200 [thread overview]
Message-ID: <20161024121202.GE3142@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161024120411.GA27567@krava>
On Mon, Oct 24, 2016 at 02:04:11PM +0200, Jiri Olsa wrote:
> On Mon, Oct 24, 2016 at 01:29:45PM +0200, Peter Zijlstra wrote:
> > Hurm, then again, I imagine that after unhash_process the PID/TID could
> > be instantly re-used and then we're still confused.
>
> sounds bad.. I haven't checked the related pid_alive code,
> but shouldn't we already get the EXIT event in this case?
It has, perf_event_exit_task() happens before we unhash.
But a per-cpu event that has PID/TID reporting on will run into this.
We'll observe 'funny' values between the unhash and the next context
switch.
next prev parent reply other threads:[~2016-10-24 12:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <318B87A793BE164187D8851D6CE09D64371C8811@shsmsx102.ccr.corp.intel.com>
2016-10-24 9:53 ` hit a KASan bug related to Perf during stress test Peter Zijlstra
2016-10-24 11:15 ` Oleg Nesterov
2016-10-24 11:24 ` Peter Zijlstra
2016-10-24 12:02 ` Oleg Nesterov
2016-10-24 12:10 ` Oleg Nesterov
2016-10-24 12:22 ` Peter Zijlstra
2016-10-24 12:29 ` Oleg Nesterov
2016-10-24 12:38 ` Peter Zijlstra
2016-10-24 13:25 ` Oleg Nesterov
2016-10-24 13:40 ` Oleg Nesterov
2016-10-24 14:17 ` Peter Zijlstra
2016-10-24 14:36 ` Peter Zijlstra
2016-10-24 15:39 ` Oleg Nesterov
2016-10-24 15:53 ` Oleg Nesterov
2016-10-25 6:55 ` Ni, BaoleX
2016-10-25 9:28 ` Peter Zijlstra
2016-10-25 14:41 ` Oleg Nesterov
2016-10-26 9:03 ` Peter Zijlstra
2016-10-26 16:10 ` Oleg Nesterov
2016-10-24 12:19 ` Peter Zijlstra
2016-10-24 11:27 ` Peter Zijlstra
2016-10-24 11:29 ` Peter Zijlstra
2016-10-24 12:04 ` Jiri Olsa
2016-10-24 12:12 ` Peter Zijlstra [this message]
2016-10-24 12:11 ` Peter Zijlstra
2016-10-24 12:21 ` Oleg Nesterov
2016-10-24 12:27 ` Peter Zijlstra
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