Re: [Patch v2] sysfs: add lockdep class support to s_active

[Cong Wang]

Eric W. Biederman wrote:
> Amerigo Wang <amwang@xxxxxxxxxx> writes:
>
> > Recently we met a lockdep warning from sysfs during s2ram or cpu hotplug.
> > As reported by several people, it is something like:
>
> The interesting case is the cpu hotplug is actually a problem.  It isn't
> useful to get a complaint about the non-problems code paths triggered
> by pm.  However my earlier review spotted a real deadlock case.  Where
> in one of the sysfs attributes we iterate over the list of online cpus
> and that appeared to an attribute that removing a cpu would remove
> from sysfs...

You are referring this one:
http://marc.info/?l=linux-kernel&m=126474021428905&w=2
?

Hmm, yeah, I missed that the lock it is holding is not s_active, thus so
not be the case we are trying to fix here.

Thanks for pointing this out.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/