suspect UBIFS async operations causing issues during reboot

[Richard Weinberger]

On Wed, Nov 5, 2014 at 9:32 AM, Scott Branden <sbranden at broadcom.com> wrote:
> We are doing reboot testing with UBIFS on the 3.10 kernel with a new chipset
> we are working on.
>
> Over 1000's of reboots we eventually find that the NAND has uncorrectable
> ECC errors reported on a random page when it is mounted.
>
> We have found the problem is that a NAND erase operation is in progress when
> the reboot occurs. Since the NAND is in the middle of the erase operation
> the page is mostly FF with some random bits not erased when the reboot
> occurs.
>
> We suspect the problem is the asynchronous nature of the UBIFS operations.
> Perhaps the small write buffer that can take 3-5 seconds to be written or
> some other operation occuring in UBI/UBIFS?  I don't think the shutdown of
> the filesystem is dealing with all the threads properly.

And what about powercuts?
UBI/UBIFS was designed to survive powercuts.
If your NAND shows strange issues even after a clean reboot something nasty is
going on. Does your driver pass all UBI/MTD test?

-- 
Thanks,
//richard