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Subject: Re: [PATCH 1/2] x86/intel_rdt: Check monitor group vs control group
 membership earlier
To:     Valentin Schneider <valentin.schneider@arm.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        Fenghua Yu <fenghua.yu@intel.com>,
        Reinette Chatre <reinette.chatre@intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>
References: <20201118180030.22764-1-valentin.schneider@arm.com>
 <20201118180030.22764-2-valentin.schneider@arm.com>
From:   James Morse <james.morse@arm.com>
Message-ID: <613d0854-597e-6ed7-05ca-70310c7b887d@arm.com>
Date:   Fri, 20 Nov 2020 14:53:15 +0000
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Hi Valentin,

On 18/11/2020 18:00, Valentin Schneider wrote:
> A task can only be moved between monitor groups if both groups belong to
> the same control group. This is checked fairly late however: by that time
> we already have appended a task_work() callback.

(is that a problem? It's needed to do the kfree())


> Check the validity of the move before getting anywhere near task_work
> callbacks.

This saves the kzalloc()/task_work_add() if it wasn't going to be necessary.

Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James