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From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>,
	linux-kernel@vger.kernel.org, dvlasenk@redhat.com
Subject: Re: [PATCH v2] Make PTRACE_SEIZE set ptrace options specified in 'data' parameter
Date: Tue, 13 Sep 2011 17:00:04 +0900	[thread overview]
Message-ID: <20110913080004.GF11397@mtj.dyndns.org> (raw)
In-Reply-To: <20110911181442.GA22239@redhat.com>

On Sun, Sep 11, 2011 at 08:14:42PM +0200, Oleg Nesterov wrote:
> We need to rework the locking, yes. But we need the lock which protects
> the parent's list_head (currently we rely on tasklist). Yes, a single
> lock can't help. We already use ->cred_guard_mutex though.
> 
> This needs more thinking, but imho child->siglock is pointless here.

But we can at least guarantee that if ->ptrace is set (or clear) while
tracee's siglock is held, its ->parent points to the tracer (or not).
At any rate, AFAICS, this currently doesn't really matter.  I
suggested it mainly because it would make the locking change easier.

Thanks.

-- 
tejun

      reply	other threads:[~2011-09-13  8:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-07 21:40 [PATCH v2] Make PTRACE_SEIZE set ptrace options specified in 'data' parameter Denys Vlasenko
2011-09-07 23:55 ` Pedro Alves
2011-09-08  0:44 ` Tejun Heo
2011-09-08 18:17   ` Oleg Nesterov
2011-09-11  2:05     ` Tejun Heo
2011-09-11 18:14       ` Oleg Nesterov
2011-09-13  8:00         ` Tejun Heo [this message]

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