On Tue, Feb 15, 2022 at 04:53:25PM +0000, Pearson, Robert B wrote: > > > spinlock_irqsave() > > > write_lock_bh() > > > write_unlock_bh() > > > spinunlock_irqrestore() > > > > > Which is illegal locking. > > > > > Jason > > > Jason, can you tell me what the problem is with this. I'm not fighting it just want to know. I don't know the exact reason, judging from the code it looks like the implementation of unlock_bh is allowed to assume hard irqs were not blocked and unblock them - probably some micro-optimization. I don't think there is a deadlock issue with the above because irqsave is a superset of the _bh varient. Jason
