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da33e87bd2
Next up on our list of race windows to close is another one during iommu_device_register() - it's now OK again for multiple instances to run their bus_iommu_probe() in parallel, but an iommu_probe_device() can still also race against a running bus_iommu_probe(). As Johan has managed to prove, this has now become a lot more visible on DT platforms wth driver_async_probe where a client driver is attempting to probe in parallel with its IOMMU driver - although commitb46064a188("iommu: Handle race with default domain setup") resolves this from the client driver's point of view, this isn't before of_iommu_configure() has had the chance to attempt to "replay" a probe that the bus walk hasn't even tried yet, and so still cause the out-of-order group allocation behaviour that we're trying to clean up (and now warning about). The most reliable thing to do here is to explicitly keep track of the "iommu_device_register() is still running" state, so we can then special-case the ops lookup for the replay path (based on dev->iommu again) to let that think it's still waiting for the IOMMU driver to appear at all. This still leaves the longstanding theoretical case of iommu_bus_notifier() being triggered during bus_iommu_probe(), but it's not so simple to defer a notifier, and nobody's ever reported that being a visible issue, so let's quietly kick that can down the road for now... Reported-by: Johan Hovold <johan@kernel.org> Fixes:bcb81ac6ae("iommu: Get DT/ACPI parsing into the proper probe path") Signed-off-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/88d54c1b48fed8279aa47d30f3d75173685bb26a.1745516488.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel <jroedel@suse.de>