Aw: [PATCH v6 00/11] Clean up "mediatek,larb"

[Yong Wu]

On Wed, 2021-07-14 at 10:59 +0200, Frank Wunderlich wrote:
> Hi,
> 
> sorry this (or the 2 depency-series) cause a NULL Pointer deref in iommu_group_remove_device on mt7623/bpi-r2

Hi Frank,

Thanks for your report. mt7623 use mtk_iommu_v1.c.

I will try to reproduce this locally.

> 
> i wonder why on bootup a cleanup is run, but have no hint about this.
> 
> since "dts: mtk-mdp: remove mediatek, vpu property from primary MDP device" all is good, i guess problem comes up while removing larb with DT
> 
> this is backtrace
> 
> [    6.274465] PC is at iommu_group_remove_device+0x28/0x148
> [    6.279877] LR is at iommu_release_device+0x4c/0x70
> 
> [    6.674347] Backtrace:
> [    6.676797] [<c0c9c37c>] (iommu_group_remove_device) from [<c06bf028>] (iomm)
> [    6.686221]  r7:00000000 r6:c06bf04c r5:c0d7a1ac r4:c21fc010
> [    6.691883] [<c06befdc>] (iommu_release_device) from [<c06bf064>] (remove_io)
> [    6.700689]  r5:00000000 r4:00000000
> [    6.704265] [<c06bf04c>] (remove_iommu_group) from [<c0733434>] (bus_for_eac)
> [    6.712725] [<c07333ac>] (bus_for_each_dev) from [<c06bf658>] (bus_set_iommu)
> [    6.720753]  r6:c331f440 r5:c1406f58 r4:ffffffea
> [    6.725370] [<c06bf5a0>] (bus_set_iommu) from [<c06c1e88>] (mtk_iommu_probe+)
> [    6.733484]  r7:c32db0b8 r6:c21f9c00 r5:c331f1c0 r4:00000000
> [    6.739145] [<c06c1bfc>] (mtk_iommu_probe) from [<c0738c14>] (platform_probe)
> [    6.747176]  r10:c21f9c10 r9:c2496f54 r8:c14623b8 r7:c14623b8 r6:c1405b90 r50
> [    6.755012]  r4:00000000
> [    6.757544] [<c0738ba8>] (platform_probe) from [<c0735968>] (really_probe.pa)
> [    6.766006]  r7:c14623b8 r6:c1405b90 r5:00000000 r4:c21f9c10
> [    6.771667] [<c07358a0>] (really_probe.part.0) from [<c0735cec>] (really_pro)
> [    6.779866]  r7:c21f9c10 r6:c2549e74 r5:c1405b90 r4:c21f9c10
> [    6.785527] [<c0735ca4>] (really_probe) from [<c0735de0>] (__driver_probe_de)
> [    6.793984]  r5:c1405b90 r4:c21f9c10
> [    6.797560] [<c0735d30>] (__driver_probe_device) from [<c0735fa0>] (driver_p)
> [    6.806543]  r9:c2496f54 r8:00000008 r7:c21f9c10 r6:c2549e74 r5:c14c6ec8 r4:4
> [    6.814291] [<c0735f5c>] (driver_probe_device) from [<c0736410>] (__device_a)
> [    6.823448]  r9:c2496f54 r8:00000000 r7:c21f9c10 r6:c2549e74 r5:c1405b90 r4:1
> [    6.831196] [<c073635c>] (__device_attach_driver) from [<c0733540>] (bus_for)
> [    6.840007]  r7:c14623b8 r6:c073635c r5:c2549e74 r4:00000000
> [    6.845669] [<c07334ac>] (bus_for_each_drv) from [<c07357e8>] (__device_atta)
> [    6.854044]  r6:00000001 r5:c21f9c54 r4:c21f9c10
> [    6.858662] [<c07356e4>] (__device_attach) from [<c073662c>] (device_initial)
> [    6.867207]  r6:c21f9c10 r5:c1406f58 r4:c1406ca0
> [    6.871825] [<c0736610>] (device_initial_probe) from [<c07346dc>] (bus_probe)
> [    6.880454] [<c0734648>] (bus_probe_device) from [<c0734cc8>] (deferred_prob)
> 
> 
> bisect shows this commit as breaking:
> 
> Author: Yong Wu <yong.wu at mediatek.com>
> Date:   Wed Jul 14 10:56:17 2021 +0800
> 
>     iommu/mediatek: Add probe_defer for smi-larb
> 
>     Prepare for adding device_link.
> 
> regards Frank