Re: MTD : Kernel oops when remounting ubifs as read/write

[Artem Bityutskiy <dedekind1@gmail.com>]

On Thu, 2013-03-14 at 09:54 +0000, Mark Jackson wrote:
> On 14/03/13 09:13, Artem Bityutskiy wrote:
> > On Wed, 2013-03-13 at 11:12 +0000, Mark Jackson wrote:
> >> Sorry ... this just locks up the unit.
> > 
> > OK, I've reproduced the issue with 3.9-rc2 in nandsim, see the details
> > below. The patch I proposed did not get the error path correctly, but it
> > does fix the issue.
> > 
> > I think what you treat as "lockup" is the fixup process. UBIFS basically
> > reads the entire UBI volume and writes it back. And it uses the atomic
> > change UBI service, which means it also calculates CRC of everything it
> > writes. And this all just takes a lot of time. This has to be done only
> > once on the first mount.
> 
> Okay ... I've retried, but how long is "a lot of time" ?
> 
> I've waited 15 minutes and still nothing.
> 
> And I can see that there's no activity on the NAND chip select !?!
> 
> I'll put some debug info into the fixup routines to see if I can trace what's going on.

Just to make sure - try this last patch I sent. I did test it with
nandsim at least, and I am sure it works. I did not test at all the
first one.

And yes, debug messages would be useful, just do not forget to add the
'ignore_loglevel' kernel boot option, otherwise you won't see the
messages on your console, since they are of KERN_DEBUG level.

You may have other issues which cause lockup, e.g., in driver level. It
makes sense to validate your flash with MTD test modules.

-- 
Best Regards,
Artem Bityutskiy