Re: regression in xgene-enet in 4.8-rc series, oops from xgene_enet_probe

Hi Riku,

quoted

When the driver is configured as kernel module and when it gets
unloaded and reloaded, kernel crash was observed.  This patch
addresses the software cleanup by doing the following,

- Moved register_netdev call after hardware is ready
- Since ndev is not ready, added set_irq_name to set irq name
- Since ndev is not ready, changed mdio_bus->parent to pdev->dev
- Replaced netif_start(stop)_queue by netif_tx_start(stop)_queues
- Removed napi_del call since it's called by free_netdev
- Added dev_close call, within remove
- Added shutdown callback
- Changed to use dmam_ APIs

Bisecting points this patch, commited as
cb0366b7c16427a25923350b69f53a5b1345a34b the cause of oops when
booting apm mustang:

[    1.670201] ------------[ cut here ]------------
[    1.674804] WARNING: CPU: 2 PID: 1 at ../net/core/dev.c:6696
rollback_registered_many+0x60/0x300
[    1.683543] Modules linked in: realtek
[    1.687291]
[    1.688774] CPU: 2 PID: 1 Comm: swapper/0 Not tainted
4.8.0-rc2-00037-g3ec60b92d3ba #1
[    1.696648] Hardware name: APM X-Gene Mustang board (DT)
[    1.701930] task: ffff8003ee078000 task.stack: ffff8003ee054000
[    1.707819] PC is at rollback_registered_many+0x60/0x300
[    1.713102] LR is at rollback_registered_many+0x30/0x300
[    1.718384] pc : [] lr : [] pstate: 20000045
[    1.725739] sp : ffff8003ee057b00
[    1.729034] x29: ffff8003ee057b00 x28: ffff8003eda1a000
[    1.734338] x27: 0000000000000002 x26: ffff8003ebcba970
[    1.739641] x25: ffff8003eda1a208 x24: ffff8003eda1a010
[    1.744945] x23: ffff8003ee057c58 x22: ffff8003ebcba000
[    1.750247] x21: 00000000ffffffed x20: ffff8003ee057b70
[    1.755549] x19: ffff8003ee057b50 x18: ffff000008dfafff
[    1.760852] x17: 0000000000000007 x16: 0000000000000001
[    1.766154] x15: ffff000008ce2000 x14: ffffffffffffffff
[    1.771458] x13: 0000000000000008 x12: 0000000000000030
[    1.776760] x11: 0000000000000030 x10: 0101010101010101
[    1.782062] x9 : 0000000000000000 x8 : ffff8003df80c700
[    1.787365] x7 : 0000000000000000 x6 : 0000000000000001
[    1.792668] x5 : dead000000000100 x4 : dead000000000200
[    1.797971] x3 : ffff8003ebcba070 x2 : 0000000000000000
[    1.803273] x1 : ffff8003ee057b00 x0 : ffff8003ebcba000
[    1.808575]
[    1.810057] ---[ end trace 93f1dda704e63533 ]---
[    1.814648] Call trace:
[    1.816207] ata2: SATA link down (SStatus 0 SControl 4300)
[    1.822535] Exception stack(0xffff8003ee057930 to 0xffff8003ee057a60)
[    1.828941] 7920:
ffff8003ee057b50 0001000000000000
[    1.836729] 7940: ffff8003ee057b00 ffff000008773c18
ffff8003ee057980 ffff000008849a1c
[    1.844517] 7960: 0000000000000009 ffff000008e50000
ffff8003ee0579a0 ffff0000086eb03c
[    1.852305] 7980: ffff000008dbcde8 ffff8003fffe1ca0
0000000000000040 ffff8003ee057998
[    1.860094] 79a0: ffff8003ee0579e0 ffff0000086eb1b0
0000000000000004 ffff8003ee057a4c
f8003ebcba000 ffff8003ee057b00
[    1.875669] 79e0: 0000000000000000 ffff8003ebcba070
dead000000000200 dead000000000100
[    1.883457] 7a00: 0000000000000001 0000000000000000
ffff8003df80c700 0000000000000000
[    1.884198] ata4: SATA link down (SStatus 0 SControl 4300)
[    1.884211] ata3: SATA link down (SStatus 0 SControl 4300)
[    1.902153] 7a20: 0101010101010101 0000000000000030
0000000000000030 0000000000000008
[    1.909941] 7a40: ffffffffffffffff ffff000008ce2000
0000000000000001 0000000000000007
[    1.917730] [] rollback_registered_many+0x60/0x300
[    1.924050] [] rollback_registered+0x28/0x40
[    1.929852] [] unregister_netdevice_queue+0x78/0xb8
[    1.936259] [] unregister_netdev+0x20/0x30
[    1.941889] [] xgene_enet_probe+0x638/0xf98
[    1.947605] [] platform_drv_probe+0x50/0xb8
[    1.953320] [] driver_probe_device+0x204/0x2b0
[    1.959294] [] __driver_attach+0xac/0xb0
[    1.964751] [] bus_for_each_dev+0x60/0xa0
[    1.970293] [] driver_attach+0x20/0x28
[    1.975576] [] bus_add_driver+0x1d0/0x238
[    1.981118] [] driver_register+0x60/0xf8
[    1.986574] [] __platform_driver_register+0x40/0x48
[    1.992982] [] xgene_enet_driver_init+0x18/0x20
[    1.999044] [] do_one_initcall+0x38/0x128
[    2.004588] [] kernel_init_freeable+0x1ac/0x250
[    2.010651] [] kernel_init+0x10/0x100
[    2.015847] [] ret_from_fork+0x10/0x40
[    2.021152] network todo 'eth%d' but state 0

Picked up from:

https://storage.kernelci.org/mainline/v4.8-rc2-37-g3ec60b92d3ba/arm64-defconfig/lab-cambridge/boot-apm-mustang.html

Visible on all mainline/apt-mustang boot reports. net-next seems to
have a fix for this.

Iyappan will follow up if required. But I notice that you are using
1.13.xx boot loader. The latest official released boot loader version
is 1.15.23 (from late 2015). I would suggest and recommend that you
upgrade if possible.

-Loc
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