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Date: Fri, 7 Jan 2011 20:49:13 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: Dario Faggioli <raistlin@linux.it>, Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel <linux-kernel@vger.kernel.org>, torbenh <torbenh@gmx.de>,
        john.stultz@linaro.org, Ingo Molnar <mingo@elte.hu>,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] Read THREAD_CPUTIME clock from other  processes.
Message-ID: <20110107194913.GA29536@redhat.com>
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On 01/07, Roland McGrath wrote:
>
> > Yes, I was worried about possible security issues too. But, it seems,
> > /proc/pid/task/tid/stat (do_task_stat) shows ->utime/stime anyway.
>
> This is constrained by ptrace_may_access(task, PTRACE_MODE_READ).

Well, ptrace_may_access() protects only get_wchan/eip/esp, but
not utime/stime.

> That's good, but it should be mentioned so that next year someone doesn't
> come back with a "there's no reason you shouldn't be able to" and go
> unchallenged.

Yes, agreed. The changelog should be improved.

Oleg.