From: Naman Jain <[email protected]> Sent: Tuesday, August 18, 2026 12:31 AM > > On 8/18/2026 10:40 AM, Michael Kelley wrote: > > From: Naman Jain <[email protected]> Sent: Monday, August 10, > > 2026 2:07 AM
[snip] > > > > Sashiko pointed out that irq_chip_retrigger_hierarchy() doesn't check > > the outermost domain -- it immediately goes the parent. In v1 of this patch > > series, you categorized this as a false positive. But I don't understand > > your explanation. Even if there aren't currently any outermost domains > > with a custom retrigger function, there could be at some point in the > > future. So it seems wrong to skip it. But maybe I'm missing something. > > Could you elaborate on your reasoning? > > > > Michael > > > > irq_chip_retrigger_hierarchy() deliberately skips the chip passed to it > and begins with its parent, i.e. apic_retrigger_irq(). The new code was > doing the same. However, if someone adds a custom .irq_retrigger, hoping > that it would get executed, it would not. > > Sashiko's example was valid in principle, but it is not relevant to > these device interrupts because desc->irq_data is the outer > MSI/IOAPIC/Hyper-V chip. The LAPIC data is its parent, not the starting > data. I found no device IRQ in this path whose descriptor starts > directly at lapic_controller. > > I am all in for adding this as a fallback - > + if (chip->irq_retrigger) > + ret = chip->irq_retrigger(data); > + else > + ret = irq_chip_retrigger_hierarchy(data); > > This should solve this problem while still covering the chips which can > forget to add a retrigger function. > > Please let me know if this looks good to you. In principle, I think what you have is correct. But there's a problem in that irq_chip_retrigger_hierarchy() isn't defined unless CONFIG_IRQ_DOMAIN_HIERARCHY=y. try_retrigger() is what you want, but it's static. You could add the #ifdef's here like in try_retrigger(), but the same problem will occur in Patch 3 with msi_set_affinity(). Really need a non-static version of try_retrigger(). Or maybe just doing the #ifdef's here and in msi_set_affinity() is the simplest approach. I don't have a strong opinion either way. Sorry this is getting so messy .... Michael
