Date: Tue, 8 Aug 2017 15:18:19 +0200
From: Thomas Meyer <thomas@m3y3r.de>
To: Willy Tarreau <w@1wt.eu>
Cc: rob@landley.net, linux-kernel@vger.kernel.org
Subject: Re: INITRAMFS_SOURCE broken by
 6e19eded3684dc184181093af3bff2ff440f5b53?
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 <20170808120442.GE27367@1wt.eu>
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On Tue, Aug 08, 2017 at 02:04:42PM +0200, Willy Tarreau wrote:
> Hi Thomas,
> 
> On Tue, Aug 08, 2017 at 01:46:25PM +0200, Thomas Meyer wrote:
> > Hi,
> > 
> > did the commit 6e19eded3684dc184181093af3bff2ff440f5b53 break a linux kernel
> > build with an included ramdisk?
> > 
> > As fas as I understand you must expliclity add rootfstype=ramfs to the kernel
> > command line to boot from the included ramfsdisk?
> > 
> > bug or feature?
> 
> Strange, I'm running my kernels with the modules packaged inside the initramfs
> and never met this problem even after this commit (my 4.9 kernels are still
> packaged this way and run fine). And yes, I do have TMPFS enabled. I can't
> tell whether tmpfs or ramfs was used however given that at this level I don't
> have all the tools available to report the FS type (and proc says "rootfs").
> Are you sure you're not missing anything ?
Pretty much I miss something!

I see that the embedded ramdisk is populated in populate_rootfs()
without any errors.
But later it fails in mount_root -> mount_block_root with:

[   27.070000] VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6
[   27.070000] Please append a correct "root=" boot option; here are the available partitions:
[   27.070000] DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify explicit textual name for "root=" boot option.
[   27.070000] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

but adding rootfstype=ramfs seems to end up with an empty ramfs?!

any hint is welcome what I may miss here.

with kind regards
thomas
> 
> Willy