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Subject: Re: [PATCH] arm64: mm: support setting page attributes for debug
 situation
To:     Will Deacon <will@kernel.org>
CC:     <catalin.marinas@arm.com>, <anshuman.khandual@arm.com>,
        <akpm@linux-foundation.org>, <willy@infradead.org>,
        <ard.biesheuvel@arm.com>, <tglx@linutronix.de>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <hushiyuan@huawei.com>,
        <linfeilong@huawei.com>
References: <5a3ab728-b895-0930-9540-5e9c586e8858@huawei.com>
 <20200116110914.GA16345@willie-the-truck>
From:   Yunfeng Ye <yeyunfeng@huawei.com>
Message-ID: <cc61e0d5-b1cb-51b4-8d33-5a339fe59f1b@huawei.com>
Date:   Wed, 22 Jan 2020 11:46:06 +0800
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On 2020/1/16 19:09, Will Deacon wrote:
> On Fri, Jan 10, 2020 at 03:47:41PM +0800, yeyunfeng wrote:
>> When rodata_full is set or pagealloc debug is enabled, block mappings or
>> contiguou hints are no longer used for linear address area. Therefore,
>> support setting page attributes in this case is useful for debugging
>> memory corruption problems.
>>
>> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
>> ---
>>  arch/arm64/mm/pageattr.c | 18 ++++++++++++++----
>>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> Although I can kind of see what you're getting at, I'm not keen on merging
> this without a user. If you're just referring to random debug hacks, then I
> think this change could be part of those too.
> 
Ok, thanks, I think when pagealloc debug is enabled, it is better not limited
to the vmap area only. and when kernel memory corruption problems happen, it's
useful to call set_memory_ro() function to debug these problem.

> Will
> 
> .
>