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 14:22:10 +0200 [thread overview]
Message-ID: <20161024122210.GM3102@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161024121030.GA17007@redhat.com>
On Mon, Oct 24, 2016 at 02:10:31PM +0200, Oleg Nesterov wrote:
> --- x/kernel/pid.c
> +++ x/kernel/pid.c
> @@ -526,8 +526,11 @@ pid_t __task_pid_nr_ns(struct task_struc
> if (!ns)
> ns = task_active_pid_ns(current);
> if (likely(pid_alive(task))) {
> - if (type != PIDTYPE_PID)
> + if (type != PIDTYPE_PID) {
> + if (type == PIDTYPE_TGID)
> + type = PIDTYPE_PID;
> task = task->group_leader;
> + }
Aah, that makes much more sense ;-)
> nr = pid_nr_ns(rcu_dereference(task->pids[type].pid), ns);
> }
> rcu_read_unlock();
Still, I wonder if returning 0 is the right thing. 0 is a 'valid' PID
for the init/idle task.
And we still have the re-use issue for the TID, because when we get here
TID is already unhashed too afaict, it just doesn't explode because we
don't deref freed memory.
next prev parent reply other threads:[~2016-10-24 12:22 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 [this message]
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
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