linux-kernel - Re: [PATCH RESEND] initramfs: cleanup incomplete rootfs

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Message-ID: <744e7bcb-9315-0283-67c5-c2cb2d094251@sysgo.com>
Date:   Mon, 11 Feb 2019 08:56:32 +0100
From:   David Engraf <david.engraf@...go.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Dominik Brodowski <linux@...inikbrodowski.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Arnd Bergmann <arnd@...db.de>,
        Luc Van Oostenryck <luc.vanoostenryck@...il.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] initramfs: cleanup incomplete rootfs

On 09.02.19 at 11:35, Andy Shevchenko wrote:
> On Sat, Feb 9, 2019 at 12:08 AM Andrew Morton <akpm@...ux-foundation.org> wrote:
>> On Fri, 8 Feb 2019 21:45:21 +0200 Andy Shevchenko <andy.shevchenko@...il.com> wrote:
>>> On Tue, Oct 30, 2018 at 5:22 PM David Engraf <david.engraf@...go.com> wrote:
>>>>
>>>> Unpacking an external initrd may fail e.g. not enough memory. This leads
>>>> to an incomplete rootfs because some files might be extracted already.
>>>> Fixed by cleaning the rootfs so the kernel is not using an incomplete
>>>> rootfs.
>>>
>>> This breaks my setup where I have U-boot provided more size of
>>> initramfs than needed. This allows a bit of flexibility to increase or
>>> decrease initramfs compressed image without taking care of bootloader.
>>> The proper solution is to do this if we sure that we didn't get enough
>>> memory, otherwise I can't consider the error fatal to clean up rootfs.
>>
>> OK, thanks.  Maybe David can suggest a fix - I'll queue up a revert
>> meanwhile.
>>
>> I don't really understand the failure.  Why does an oversized initramfs
>> cause unpack_to_rootfs() to fail?
> 
> In my case I have got "Junk in compressed archive". I don't know (I
> would check if needed) which exact condition I got  since there are
> three places with this message. The file itself smaller than the size
> passed through bootparam. So, when decomression is finished
> (successfully!) we still have a garbarge in the memory which is not
> related to archive. Message per se is okay to have, though I consider
> this non-fatal.

I can reproduce this special case. The unpacking decompresses the whole 
size instead of checking the archive size. I will have a look how to get 
the real archive size.

Best regards
- David