UBI: Race between fastmap_write and wear_leveling_worker

[Richard Weinberger]

Anders,

On 25.08.2016 08:52, Anders Olofsson wrote:
> On 2016-08-24 17:04, Richard Weinberger wrote:
>> Anders,
>>
>> On Wed, Aug 24, 2016 at 1:37 PM, Anders Olofsson <pingu at mazeda.se> wrote:
>>> After enabling fastmap I sometimes get the following warning at boot:
>>>
>>
>> Hehe, you're lucky I've recently fixed an issue in this area, can you
>> please try:
>> http://lists.infradead.org/pipermail/linux-mtd/2016-August/068919.html
>>
>> I did these fixes on top of an rather old customer kernel and started
>> upstreaming
>> them.
>>
> 
> Tested it and from what I can tell it solves my problem as well. I've run a bunch of reboots and the wear leveling worker no longer runs while the fastmap is being updated.
> 
> Good work and thanks a lot for solving it so quickly.

How do you test? I wonder how you can trigger this so easily.
The said patch emerged while a customer did excessive Fastmap testing
and the race appeared only once. I found it while staring at the code.

But it is good to see that finally after years embedded Folks start
using Fastmap and non-obvious issues can get sorted out.

Thanks,
//richard