On Thu, Jul 24, 2014 at 04:38:28PM -0400, Waiman Long wrote: > Yes, I think I may have a solution for that. > > Borislav, can you apply the following patch on top of the lockdep patch to > see if it can fix the problem? > > diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c > index d24e433..507a8ce 100644 > --- a/kernel/locking/lockdep.c > +++ b/kernel/locking/lockdep.c > @@ -3595,6 +3595,12 @@ void lock_acquire(struct lockdep_map *lock, unsigned > int > raw_local_irq_save(flags); > check_flags(flags); > > + /* > + * An interrupt recursive read in interrupt context can be considered > + * to be the same as a recursive read from checking perspective. > + */ > + if ((read == 3) && in_interrupt()) > + read = 2; > current->lockdep_recursion = 1; > trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, > ip); > __lock_acquire(lock, subclass, trylock, read, check,
Just had another look at the initial patch and it cannot be right, even with the above. The problem is you cannot use in_interrupt() in check_deadlock(). Check_deadlock() must be context invariant, it should only test the chain state and not rely on where or when its called.
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