linux-kernel - Re: [PATCH] perf/x86: Reset the counter to prevent the leak for a RDPMC task

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Message-ID: <20200730165057.GC2678@hirez.programming.kicks-ass.net>
Date:   Thu, 30 Jul 2020 18:50:57 +0200
From:   peterz@...radead.org
To:     "Liang, Kan" <kan.liang@...ux.intel.com>
Cc:     mingo@...hat.com, acme@...nel.org, linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, Mark Rutland <mark.rutland@....com>,
        Andy Lutomirski <luto@...capital.net>
Subject: Re: [PATCH] perf/x86: Reset the counter to prevent the leak for a
 RDPMC task

On Thu, Jul 30, 2020 at 06:44:26PM +0200, peterz@...radead.org wrote:
> Arguably we should have perf_mmap_open() check if 'event->hw.target ==
> current', because without that RDPMC is still pointless.

event->hw.target->mm == current->mm, I suppose, otherwise accounting
goes wobbly real fast.