Re: Re: lockdep report in hibernate code

[Johannes Berg <johannes@sipsolutions.net>]

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> > We have two paths here:
> > 
> >  (a) sysfs write -> lock buffer -> call power management code 
> >      -> lock pm_mutex
> >  (b) boot code -> power management boot -> lock pm_mutex
> >      -> use name_to_dev_t() -> call sysfs -> lock buffer
> > 
> > As you can see, lockdep rightfully complains about a possible deadlock
> > scenario although of course (b) only happens once at boot at a time
> > where (a) cannot happen. And now we're wondering how to fix it.
> 
> Why not use mutex_lock_nested() for the boot-time pm_mutex lock call?

Is that going to help though? I thought lock_nested() is only for nested
within a class.

johannes

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