Messages in this thread | | | Date | Thu, 20 Aug 2020 13:40:36 +0200 | From | peterz@infradea ... | Subject | Re: [PATCH] lockdep: Do no validate wait context for novalidate class |
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On Mon, Jun 29, 2020 at 10:15:29PM +0200, Sebastian Andrzej Siewior wrote: > The novalidate class is ignored in the lockchain validation but is > considered in the wait context validation. > If a mutex and a spinlock_t is ignored by using > lockdep_set_novalidate_class() then both locks will share the same lock > class. From the wait validation point of view the mutex will then appear > like a spinlock_t and the validator will complain if another mutex will > be acquired. > > Ignore the nonvalidate locks from wait context checking.
Hurmph.. but how? There was only a single user... /me greps.
drivers/base/core.c: lockdep_set_novalidate_class(&dev->mutex); drivers/md/bcache/btree.c: lockdep_set_novalidate_class(&b->lock); drivers/md/bcache/btree.c: lockdep_set_novalidate_class(&b->write_lock);
Urgh.. there's more now :-(
So write_lock, like dev->mutex is a mutex.
Kent, what's the story with b->lock? It appears to have lockdep annotations, but then is also the novalidate class. Also neither of these lockdep_set_novalidate_class() thingies have a comment.
Anyway, all 3 users should have the same wait context, so where is the actual problem?
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