On 2014/11/21 10:08, Suravee Suthikulpanit wrote: > On 11/20/2014 07:32 PM, Thomas Gleixner wrote: >> On Thu, 20 Nov 2014, suravee.suthikulpanit@xxxxxxx wrote: >>> This patch checks if the parent domain is NULL before recursively >>> freeing >>> irqs in the parent domains. >> >> Which is nonsense, because if the thing has not been allocated in the >> first place, then it cannot explode in the free path magically, except >> there is a missing check in the allocation path error handling. >> >> And that's obviously not the case simply because this originates from: >>> [<fffffe0000449278>] pci_disable_msix+0x40/0x50 >> > > Thomas, > > In this case, I have the following irq domain hierarchy: > > [GIC] -- [GICv2m] -- [MSI] > > which recursively calling the freeing function: > > In GIC domain, it currently defines the struct irq_domain_ops.free() with : > --> irq_domain_free_irqs_top() > |--> irq_domain_free_irqs_common() > |--> irq_domain_free_irq_parent() > |--> irq_domain_free_irqs_recursive() > > and there is no check before passing the NULL domain->parent into the > irq_domain_free_irqs_recursive(), which causes the error. > > Since the GIC is the top most domain, it does not have parent domain. > So, I'm not sure what is missing from the allocation path error > handling, as you mentioned. Hi Thomas, We have had a discussion about this issue in another thread. Originally irq_domain_free_irqs_common() is designed to be used by irqdomains with parent. But there are desires to reuse it to support irqdomains without parent too for code reduction. So I suggest to change irq_domain_free_irqs_common() instead of irq_domain_free_irqs_parent() because caller of irq_domain_free_irqs_parent() should guarantee current domain do have a parent. I'm preparing a patch for this:) Regards! Gerry > > Thanks, > > Suravee -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
