On Sat, Feb 25, 2017 at 11:53:13PM -0700, Logan Gunthorpe wrote: > Changes since v4: > > * Turns out pushing the pci release code into the device release > function didn't work as I would have liked. If you try to unbind the > device with an instance open, then you hit a kernel bug at > drivers/pci/msi.c:371. (This didn't occur in v3.) This is in free_msi_irqs(): 368 for_each_pci_msi_entry(entry, dev) 369 if (entry->irq) 370 for (i = 0; i < entry->nvec_used; i++) 371 BUG_ON(irq_has_action(entry->irq + i)); I don't think this is indicating a bug in the PCI core (although I do think a BUG_ON() here is an excessive response). I think it's an indication that the driver didn't disconnect its ISR. Without more details of the failure it's hard to tell if the BUG_ON is a symptom of a problem in the driver or what. An "alive" flag feels racy, and I can't tell if it's really the best way to deal with this, or if it's just avoiding the issue. There must be other drivers with the same cleanup issue -- do they handle it the same way? > To solve this, we've moved the pci release code back into the > unregister function and reintroduced an alive flag. This time, > however, the alive flag is protected by mrpc_mutex and we're very > careful about what happens to devices still in use (they should > all be released through the timeout path and an ENODEV error > returned to userspace; while new commands are blocked with the > same error).
