[BUG] mtk-mdp3: Crash during probe in mtk-mdp3

[Sebastian Andrzej Siewior]

Hi,

On next-20260914 I saw:

| mtk-mdp3 14001000.dma-controller: deferred probe timeout, ignoring dependency
| Unable to handle kernel NULL pointer dereference at virtual address 0000000000000019
| Mem abort info:
|   ESR = 0x0000000096000004
|   EC = 0x25: DABT (current EL), IL = 32 bits
|   SET = 0, FnV = 0
|   EA = 0, S1PTW = 0
|   FSC = 0x04: level 0 translation fault
| Data abort info:
|   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
|   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
|   GCS = 0, Overlay = 0, DirtyBit = 0
| user pgtable: 4k pages, 48-bit VAs, pgdp=0000000110d36000
| [0000000000000019] pgd=0000000000000000, p4d=0000000000000000
| Internal error: Oops: 0000000096000004 [#1]  SMP
| dwmac-mediatek 11021000.ethernet end0: renamed from eth0
| Modules linked in: mtk_vcodec_dec_hw …
| CPU: 6 UID: 0 PID: 90 Comm: kworker/u32:1 Tainted: G        W           7.3.0-rc3-next-20260914 #1 PREEMPT_{RT,(full)}
| Tainted: [W]=WARN
| Hardware name: MediaTek Genio 1200 EVK-P1V2-EMMC (DT)
| Workqueue: events_unbound deferred_probe_work_func
| pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : mtk_mutex_get+0xc/0x44 [mtk_mutex]
| lr : mdp_probe+0x150/0x438 [mtk_mdp3]
| sp : ffff8000837ebb30
| x29: ffff8000837ebb30 x28: 0000000000000000 x27: 0000000000000000
| x26: 000000000000000c x25: 000000000000000d x24: ffff0000c0de3410
| x23: 0000000000000000 x22: ffff0000c0de3400 x21: 0000000000000000
| x20: ffff0000d1e56800 x19: ffff0000d1e56800 x18: ffff8000826bfd18
| x17: 3030303030303431 x16: 3a6d726f6674616c x15: 0000000000000058
| x14: ffffffffffffffff x13: 0000000000000028 x12: 0101010101010101
| x11: 7f7f7f7f7f7f7f7f x10: fefeff776473746c x9 : 0000000000000008
| x8 : ffff0000c0864500 x7 : 0000000000000000 x6 : 0000000000000020
| x5 : 0000000000000020 x4 : 0000000000000040 x3 : 0000000000000000
| x2 : ffff80007b37d040 x1 : 0000000000000000 x0 : 0000000000000019
| Call trace:
|  mtk_mutex_get+0xc/0x44 [mtk_mutex] (P)
|  platform_probe+0x5c/0xa4
|  really_probe+0xbc/0x2c0
|  __driver_probe_device+0x11c/0x184
|  driver_probe_device+0x3c/0x114
|  __device_attach_driver+0xb8/0x11c
|  bus_for_each_drv+0x88/0xe8
|  __device_attach+0xa0/0x190
|  device_initial_probe+0x50/0x54
|  bus_probe_device+0x38/0xac
|  deferred_probe_work_func+0x90/0xc8
|  process_one_work+0x188/0x4f8
|  worker_thread+0x18c/0x308
|  kthread+0x130/0x140
|  ret_from_fork+0x10/0x20
| Code: ???????? f9403c03 52800001 91006460 (39400002)
| ---[ end trace 0000000000000000 ]---

That report ist from
	https://dashboard.kernelci.org/test/maestro%3A6aa88a0d20239ade9037b72f
	https://files.kernelci.org/rt-tests-cyclictest-6aa88a0d20239ade9037b72f/log.txt.gz

This is also visible on 7.3.0-rc3:
	https://files.kernelci.org/rt-tests-cyclictest-6aa84e3720239ade90364e29/log.txt.gz

Could someone please take a look, I don't have the hardware myself.

Sebastian