Re: [PATCH 0/11] Merge ramoops and persistent_ram, generic pstore RAM backend

Greg Kroah-Hartman
2012-05-14T15:58:53Z

On Fri, May 11, 2012 at 05:15:06PM -0700, Anton Vorontsov wrote:
> Hi all,
>
> There are currently two competing debug facilities to store kernel
> messages in a persistent storage: a generic pstore and Google's
> persistent_ram. Not so long ago (https://lkml.org/lkml/2012/3/8/252),
> it was decided that we should fix this situation.
>
> Recently ramoops has switched to pstore, which basically means that
> it became a RAM backend for the pstore framework.
>
> persistent_ram+ram_console and ramoops+pstore have almost the same
> features, except:
>
> 1. Ramoops doesn't support ECC. Having ECC is useful when a hardware
> reset was used to bring the machine back to life (i.e. a watchdog
> triggered). In such cases, RAM may be somewhat corrupt, but
> usually it is restorable.
>
> 2. Pstore doesn't support logging kernel messages in run-time, it only
> dumps dmesg when kernel oopses/panics. This makes pstore useless for
> debugging hangs caused by HW issues or improper use of HW (e.g.
> weird device inserted -> driver tried to write a reserved bits ->
> SoC hanged. In that case we don't get any messages in the pstore.
>
> These patches solve the first issue, plus move things to their
> proper places. Patches that will fix the second issue are pending.

I've applied the first 7 patches, as they were localized to the
drivers/staging/android/ directory, but in order for me to apply the
rest, I need acks from the respective subsystem maintainers.

pstore developers, what do you say about these changes, are you ok with
them?

thanks,

greg k-h