Subject: 3.17-rc2: root=/dev/mmcblk0p2 command line parsing fails

From: [email-masked] (Pavel Machek)
Date: Tue, 9 Sep 2014 13:49:41 +0200

Hi!

> > The problem is still there in 3.17-rc2. 3.16 does not have the
> > problem. Messages are still similar:
> >
> > mmc0: new high speed SDHC card at address b368
> > mmcblk0: mmc0:b368 USD   7.45 GiB
> >  mmcblk0: p1 p2 p3 p4
> > VFS: Cannot open root device "mmcblk0p2" or unknown-block(0,0): error
> > -6
> > Please append a correct "root=" boot option; here are the available
> > partitions:
> > b300         7822336 mmcblk0  driver: mmcblk
> >   b301          102400 mmcblk0p1 00082434-01
> >   b302         1048576 mmcblk0p2 00082434-02
> >   b303            1024 mmcblk0p3 00082434-03
> >   b304         6086656 mmcblk0p4 00082434-04
> > Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> > 3.17.0-rc2-00368-gec0400b-dirty #83
> >
> >
> > What is going on there? Clearly partition table was parsed and
> > partitions are available; does the mention of unknown-block(0,0) mean
> > that kernel failed to parse the command line?
> >
> > I replaced "root=/dev/mmcblk0p2" with "root=b302" and have a booting
> > system.
> 
> 
> Can you do a bisect? 3.17-rc2 booted fine for me today:
> 
> EXT3-fs (mmcblk0p2): mounted filesystem with ordered data mode
> VFS: Mounted root (ext3 filesystem) on device 179:2.
> Freeing unused kernel memory: 252K (c052d000 - c056c000)
> random: nonblocking pool is initialized

Bisect would be hard... and I believe the problem is somewhere in
block layer now -- not socfpga-specific.

Best regards,
								Pavel

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