Re: INITRAMFS_SOURCE broken by 6e19eded3684dc184181093af3bff2ff440f5b53?

From: Thomas Meyer
Date: Tue Aug 08 2017 - 09:18:29 EST


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