Re: Timeout in denali.c on Micron nandflash (Altera SoC)

[Thorsten Christiansson <thorsten.christiansson@idquantique.com>]

Hello Richard,

On advice from Altera, I have been testing using JFFS2 directly on top
of MTD, and thereby bypassing the UBI completely. At first it looked
promising, but I have seen the same 'timeout' here as well.

I will get back to running some tests with an up-to-date kernel, and will
keep you posted.


Thanks,

Thorsten

On 03/09/2017 11:09 PM, Richard Weinberger wrote:
> Thorsten,
>
> On Tue, Mar 7, 2017 at 2:32 PM, Thorsten Christiansson
> <thorsten.christiansson@idquantique.com> wrote:
>> Hi all,
>>
>> I'm using Linux on an Altera SoC (Arria V), on which I'm using UBIFS on a
>> nandflash from Micron (MT29F8G08ADADAH4).  I have a 400Mb r/w partition on
>> which I have a sqlite3-based database. We're running an application that
>> reads/writes fairly small blocks. After running for about a week at moderate
>> load, I get an error message, and the filesystem becomes read-only.
>>
>> The message I get is a timeout, originating in the denali.c driver.
>> [11744.733748] timeout occurred, status = 0x0, mask = 0x4
>> [11745.733685] timeout occurred, status = 0x0, mask = 0x120
>>
>> I can also reproduce the error much faster (in ~1h) using the GNU 'stress'
>> command, writing/reading small files continuously.
>>
>> I'm using Linux 4.4, with some patches from Altera. I have compared the
>> denali.c that I'm using with the current HEAD on github, and the differences
>> appear to be only cosmetic.
>>
>> I have asked Altera for help, but their only response so far has been that
>> they can reproduce the issue on their latest SoCs (it apparently appears on
>> both Arria10 and CycloneV) with the same flash. (We have also tested with a
>> Macronix MX66U51235FMI-10G, with the same results.)
>>
>> At first we used the FASTMAP feature of the UBIFS, but then we ran into this
>> issue after only a couple of hours running at moderate load. When we
>> disabled
>> that, we thought the problem was gone, but it appears that it was only
>> hiding,
>> and now comes out to bite us after about a week.
>>
>>
>> My questions are the following:
>> - Are there any known issues with the denali driver that could cause this?
> Well, 4.4. is not very fresh. Maybe it saw fixes in recent version.
>
>> - Could it be an issue in the MTD/UBI/UBIFS layers?
> Since the denali driver prints the timeouts I'd say the root of the
> problem is there.
>
>> - Are there any other parameters that can be tuned in order to alleviate the
>>   problem?
>>
>> and of course
>> - Have I missed something obvious? I'm pulling my hair here...
> Can you please give MTD tests a try?
>

-- 
Thorsten Christiansson
Security Engineer
ID Quantique
thorsten.christiansson@idquantique.com
<mailto:thorsten.christiansson@idquantique.com>
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