Re: [PATCH v4 8/9] iommu: Remove unused argument in is_attach_deferred

Tony Lindgren
2022-03-30T14:00:49Z

Hi,

* Lu Baolu <baolu.lu@linux.intel.com> [700101 02:00]:
> The is_attach_deferred iommu_ops callback is a device op. The domain
> argument is unnecessary and never used. Remove it to make code clean.

Looks like this causes a regression for at least drivers/iommu/omap-iommu.c.

To me it seems the issue is there is no is_attach_deferred implemented, so
we get a NULL pointer dereference at virtual address 00000008:

__iommu_probe_device from probe_iommu_group+0x2c/0x38
probe_iommu_group from bus_for_each_dev+0x74/0xbc
bus_for_each_dev from bus_iommu_probe+0x34/0x2e8
bus_iommu_probe from bus_set_iommu+0x80/0xc8
bus_set_iommu from omap_iommu_init+0x88/0xcc
omap_iommu_init from do_one_initcall+0x44/0x24c

Any ideas for a fix?

It would be good to fix this quickly so we don't end up with a broken
v5.18-rc1..

For reference, this is mainline commit 41bb23e70b50 ("iommu: Remove unused
argument in is_attach_deferred").

Regards,

Tony

#regzbot ^introduced 41bb23e70b50