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From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: "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>
Subject: Re: hit a KASan bug related to Perf during stress test
Date: Mon, 24 Oct 2016 14:27:48 +0200	[thread overview]
Message-ID: <20161024122748.GO3102@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161024122123.GB17007@redhat.com>

On Mon, Oct 24, 2016 at 02:21:23PM +0200, Oleg Nesterov wrote:
> > Should we do the same for perf_event_tid() and report -1 as the pid/tid
> > in the !alive case? -1 should be an obvious invalid pid since we limit
> > the pid-space to less than 32 bits.
> 
> task_pid_nr_ns() is always safe, it calls __task_pid_nr_ns(). But yes,
> it can return zero if called after exit_notify() and/or release_task().
> 
> And while zero is not a valid pid too, I guess it can be confused with
> the idle thread's "pid" ?

Right, 0 is the idle thread.

      reply	other threads:[~2016-10-24 12:27 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
2016-10-24 12:11     ` Peter Zijlstra
2016-10-24 12:21       ` Oleg Nesterov
2016-10-24 12:27         ` Peter Zijlstra [this message]

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