linux-kernel - Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data

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Message-ID: <32b8c5e4-c8e3-0244-1b1a-ca33bd44f38a@redhat.com>
Date:   Mon, 31 Jul 2023 21:24:50 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Lorenzo Stoakes <lstoakes@...il.com>
Cc:     Baoquan He <bhe@...hat.com>, Jiri Olsa <olsajiri@...il.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Uladzislau Rezki <urezki@...il.com>,
        Matthew Wilcox <willy@...radead.org>,
        Liu Shixin <liushixin2@...wei.com>,
        Jens Axboe <axboe@...nel.dk>,
        Alexander Viro <viro@...iv.linux.org.uk>
Subject: Re: [PATCH v8 1/4] fs/proc/kcore: avoid bounce buffer for ktext data

On 31.07.23 21:21, Lorenzo Stoakes wrote:
> On Mon, Jul 24, 2023 at 08:23:55AM +0200, David Hildenbrand wrote:
>> Hi,
>>
>>>
>>> I met this too when I executed below command to trigger a kcore reading.
>>> I wanted to do a simple testing during system running and got this.
>>>
>>>     makedumpfile --mem-usage /proc/kcore
>>>
>>> Later I tried your above objdump testing, it corrupted system too.
>>>
>>
>> What do you mean with "corrupted system too" --  did it not only fail to
>> dump the system, but also actually harmed the system?
>>
>> @Lorenzo do you plan on reproduce + fix, or should we consider reverting
>> that change?
>>
>> --
>> Cheers,
>>
>> David / dhildenb
>>
> 
> Apologies I mised this, I have been very busy lately not least with book :)
> 
> Concerning, I will take a look as I get a chance. I think the whole series
> would have to be reverted which would be... depressing... as other patches
> in series eliminates the bounce buffer altogether.
> 

I spotted

https://lkml.kernel.org/r/069dd40aa71e634b414d07039d72467d051fb486.camel@gmx.de

today, maybe that's related.

-- 
Cheers,

David / dhildenb