linux-kernel - Re: [PATCH v9 28/44] arm64: mte: Reset the page tag in page->flags

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Message-ID: <cbc140bf-a949-d9cb-3c9e-92304ee40c8e@arm.com>
Date:   Thu, 12 Nov 2020 09:39:59 +0000
From:   Vincenzo Frascino <vincenzo.frascino@....com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Andrey Konovalov <andreyknvl@...gle.com>
Cc:     Will Deacon <will.deacon@....com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Evgenii Stepanov <eugenis@...gle.com>,
        Branislav Rankov <Branislav.Rankov@....com>,
        Kevin Brodsky <kevin.brodsky@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        kasan-dev@...glegroups.com, linux-arm-kernel@...ts.infradead.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9 28/44] arm64: mte: Reset the page tag in page->flags

On 11/12/20 9:31 AM, Catalin Marinas wrote:
> On Tue, Nov 10, 2020 at 11:10:25PM +0100, Andrey Konovalov wrote:
>> diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c
>> index 70a71f38b6a9..f0efa4847e2f 100644
>> --- a/arch/arm64/mm/copypage.c
>> +++ b/arch/arm64/mm/copypage.c
>> @@ -23,6 +23,7 @@ void copy_highpage(struct page *to, struct page *from)
>>  
>>  	if (system_supports_mte() && test_bit(PG_mte_tagged, &from->flags)) {
>>  		set_bit(PG_mte_tagged, &to->flags);
>> +		page_kasan_tag_reset(to);
>>  		mte_copy_page_tags(kto, kfrom);
> 
> Any reason why this doesn't have an smp_wmb() between resetting the tags
> and copying them into kto?
> 

Yes, the reason is I am not sure why it disappeared from the submitted patch ;)
I am going to respin the patch.

-- 
Regards,
Vincenzo