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Subject: Re: [PATCH] arm64: mte: Move MTE TCF0 check in entry-common
To:     Mark Rutland <mark.rutland@arm.com>, Will Deacon <will@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kasan-dev@googlegroups.com,
        Catalin Marinas <catalin.marinas@arm.com>
References: <20210408143723.13024-1-vincenzo.frascino@arm.com>
 <20210408145604.GB18211@willie-the-truck>
 <20210408150612.GA37165@C02TD0UTHF1T.local>
From:   Vincenzo Frascino <vincenzo.frascino@arm.com>
Message-ID: <e3c6fa5b-82a2-dfd9-859b-efbb9970c5e5@arm.com>
Date:   Thu, 8 Apr 2021 16:23:27 +0100
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On 4/8/21 4:06 PM, Mark Rutland wrote:
> On Thu, Apr 08, 2021 at 03:56:04PM +0100, Will Deacon wrote:
>> On Thu, Apr 08, 2021 at 03:37:23PM +0100, Vincenzo Frascino wrote:
>>> The check_mte_async_tcf macro sets the TIF flag non-atomically. This can
>>> race with another CPU doing a set_tsk_thread_flag() and the flag can be
>>> lost in the process.
>>
>> Actually, it's all the *other* flags that get lost!
>>

You are right, I need to explain this better.

...

-- 
Regards,
Vincenzo