[PATCH] iommu/omap: Fix regression in probe for NULL pointer dereference

[H. Nikolaus Schaller]

Hi,

> Am 07.04.2022 um 07:39 schrieb Tony Lindgren <tony at atomide.com>:
> 
> Hi,
> 
> * Tony Lindgren <tony at atomide.com> [220331 09:21]:
>> Commit 3f6634d997db ("iommu: Use right way to retrieve iommu_ops") started
>> triggering a NULL pointer dereference for some omap variants:
>> 
>> __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+0x44/0x24
>> 
>> This is caused by omap iommu probe returning 0 instead of ERR_PTR(-ENODEV)
>> as noted by Jason Gunthorpe <jgg at ziepe.ca>.
>> 
>> Looks like the regression already happened with an earlier commit
>> 6785eb9105e3 ("iommu/omap: Convert to probe/release_device() call-backs")
>> that changed the function return type and missed converting one place.
> 
> Can you guys please get this fix into the -rc series? Or ack it so
> I can pick it up into my fixes branch?
> 
> Without this fix booting is failing for a bunch of devices.

Yes, I can confirm that v5.18-rc1 does not even boot the GTA04 (omap3)
and OMAP5UEVM to any activity without this patch.

Seems to be an urgent fix.

BR and thanks,
Nikolaus