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Subject: Re: [RFC PATCH] rootfs: force mounting rootfs as tmpfs
To:     Mimi Zohar <zohar@linux.vnet.ibm.com>,
        Arvind Sankar <nivedita@alum.mit.edu>
Cc:     initramfs <initramfs@vger.kernel.org>,
        Taras Kondratiuk <takondra@cisco.com>,
        Victor Kamensky <kamensky@cisco.com>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        Al Viro <viro@ZenIV.linux.org.uk>,
        linux-kernel <linux-kernel@vger.kernel.org>
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 <1814af5c-170d-39c0-58fd-02eb7216e008@landley.net>
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 <a538e55c-81ca-6d59-20cf-21b47387c3e2@landley.net>
 <20180201020331.GA3774@rani.riverdale>
 <1517458921.3329.2.camel@linux.vnet.ibm.com>
From:   Rob Landley <rob@landley.net>
Message-ID: <a9249307-9c95-ea75-bc83-7b95412e6ec4@landley.net>
Date:   Thu, 1 Feb 2018 16:46:07 -0600
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On 01/31/2018 10:22 PM, Mimi Zohar wrote:
> On Wed, 2018-01-31 at 21:03 -0500, Arvind Sankar wrote:
>> On Wed, Jan 31, 2018 at 05:48:20PM -0600, Rob Landley wrote:
>>> On 01/31/2018 04:07 PM, Mimi Zohar wrote:
>>>> On Wed, 2018-01-31 at 13:32 -0600, Rob Landley wrote:>> (The old "I configured in tmpfs and am using rootfs but I want that
>>> rootfs
>>>>> to be ramfs, not tmpfs" code doesn't seem to be a real-world concern, does
>>>>> it?)
>>>>
>>>> I must be missing something.  Which systems don't specify "root=" on
>>>> the boot command line.
>>>
>>> Any system using initrd or initramfs?
>>>
>>
>> Don't a lot of initramfs setups use root= to tell the initramfs which
>> actual root file system to switch to after early boot?
> 
> With your patch and specifying "root=tmpfs", dracut is complaining:
> 
> dracut: FATAL: Don't know how to handle 'root=tmpfs'
> dracut: refusing to continue

"The kernel can't break this buggy userspace package."

"The kernel must give access to a new feature to this buggy userspace
package".

I think kernel policy asks you to pick one, but I could be wrong...

Rob