[Freedreno] drm : adv7511 module unload crash

[Rob Clark]

Looks like a spot where we don't drain a workqueue on unload.  In
general, I'd say unload is not well tested and there is a lot that can
go wrong.  It's also not something that really happens in the real
world.  Patches welcome, but I don't think it is the highest priority.

BR,
-R

On Wed, Feb 27, 2019 at 6:45 AM Vinay Simha B N <simhavcs at gmail.com> wrote:
>
> hi,
>
> manually trying to load and unload the adv7511 module,
> modprobe adv7511 - works
> rmmod adv7511 - crashes.
>
> any suggestion why module unload crashing? is it not possible to
> load/unload module for drm framework?
>
>    77.326091] Workqueue: dsi_drm_work dsi_hpd_worker [msm]
> [   77.362360] task: ffff800009fcb800 task.stack: ffff000008050000
> [   77.367665] PC is at 0xffff0000010b258c
> [   77.373264] LR is at 0xffff0000010b258c
> [   77.377083] pc : [<ffff0000010b258c>] lr : [<ffff0000010b258c>]
> pstate: 60000145
> [   77.385625] sp : ffff000008053c80
> [   77.393149] x29: ffff000008053c80 x28: 0000000000000000
> [   77.397809] x27: ffff80000eb08078 x26: ffff0000090e09e0
> [   77.402384] x25: 0000000000000001 x24: ffff000000c8d3f8
> [   77.407293] x23: ffff000000c8d428 x22: ffff80003c1612b8
> [   77.412520] x21: ffff80003c1622b8 x20: ffff80003c162018
> [   77.417732] x19: 0000000000000001 x18: 0000000000000010
> [   77.422968] x17: 0000000000000000 x16: 0000000000000000
> [   77.428169] x15: 0000000000000006 x14: ffff00008925694f
> [   77.433383] x13: ffff00000925695d x12: ffff000008b7c098
> [   77.438607] x11: 0000000000000040 x10: ffff80003d400270
> [   77.443860] x9 : ffff80003d4002e8 x8 : 0000000000000000
> [   77.449087] x7 : 000000000000003f x6 : 0000000000000001
> [   77.454303] x5 : 0000000000000000 x4 : 0000000034ceb000
> [   77.459556] x3 : 0000000000000000 x2 : ffff80003d320800
> [   77.464804] x1 : 0000000000000000 x0 : 00000000ffffff92
> [   77.470050] Process kworker/u8:0 (pid: 5, stack limit = 0xffff000008050000)
> [   77.475463] Call trace:
> [   77.482153] Exception stack(0xffff000008053b40 to 0xffff000008053c80)
> [   77.486146] 3b40: 00000000ffffff92 0000000000000000
> ffff80003d320800 0000000000000000
> [   77.491644] 3b60: 0000000034ceb000 0000000000000000
> 0000000000000001 000000000000003f
> [   77.499488] 3b80: 0000000000000000 ffff80003d4002e8
> ffff80003d400270 0000000000000040
> [   77.507349] 3ba0: ffff000008b7c098 ffff00000925695d
> ffff00008925694f 0000000000000006
> [   77.515217] 3bc0: 0000000000000000 0000000000000000
> 0000000000000010 0000000000000001
> [   77.523007] 3be0: ffff80003c162018 ffff80003c1622b8
> ffff80003c1612b8 ffff000000c8d428
> [   77.530814] 3c00: ffff000000c8d3f8 0000000000000001
> ffff0000090e09e0 ffff80000eb08078
> [   77.538620] 3c20: 0000000000000000 ffff000008053c80
> ffff0000010b258c ffff000008053c80
> [   77.546385] 3c40: ffff0000010b258c 0000000060000145
> ffff000008053c80 ffff0000010b258c
> [   77.554143] 3c60: ffffffffffffffff ffff80003c162018
> ffff000008053c80 ffff0000010b258c
> [   77.561933] [<ffff0000010b258c>] 0xffff0000010b258c
> [   77.569782] [<ffff000000c79c5c>]
> drm_helper_probe_detect_ctx+0x84/0xd0 [drm_kms_helper]
> [   77.574585] [<ffff000000c7a8f0>]
> drm_helper_hpd_irq_event+0x98/0x140 [drm_kms_helper]
> [   77.582643] [<ffff000000d5d88c>] dsi_hpd_worker+0x14/0x20 [msm]
> [   77.590395] [<ffff0000080e873c>] process_one_work+0x1cc/0x328
> [   77.596035] [<ffff0000080e88e8>] worker_thread+0x50/0x450
> [   77.601796] [<ffff0000080eea5c>] kthread+0xfc/0x128
> [   77.607038] [<ffff000008084ec8>] ret_from_fork+0x10/0x18
> [   77.611590] Code: bad PC value
> [   77.616996] ---[ end trace a867a6e04ca3e227 ]---
>
> --
> regards,
> vinaysimha
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