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

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Message-ID: <f10f06d4-9c82-41d3-a62a-09c62f254cfc@lucifer.local>
Date:   Mon, 31 Jul 2023 20:21:32 +0100
From:   Lorenzo Stoakes <lstoakes@...il.com>
To:     David Hildenbrand <david@...hat.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 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.