BUG: spinlock bad magic - lock: msm_uart_ports

[Naresh Kamboju]

The kernel BUG reported on arm64 Dragonboard 410c (APQ 8016 SBC)
while booting Linux mainline kernel 5.6.0

The kernel configs (with extra fragments) and full boot log links
provided below.

boot log:
-----------
[ 0.000000] Linux version 5.6.0 (oe-user@oe-host) (gcc version 7.3.0
(GCC), GNU ld (GNU Binutils) 2.30.0.20180208) #1 SMP PREEMPT Sun Apr
12 11:44:21 UTC 2020
[ 0.000000] Machine model: Qualcomm Technologies, Inc. APQ 8016 SBC
[ 0.000000] efi: UEFI not found.
<>
[    2.550066] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[    2.564493] SuperH (H)SCI(F) driver initialized
[    2.568321] msm_serial 78af000.serial: msm_serial: detected port #1
[    2.568457] msm_serial 78af000.serial: uartclk = 19200000
[    2.568724] 78af000.serial: ttyMSM1 at MMIO 0x78af000 (irq = 9,
base_baud = 1200000) is a MSM
[    2.572081] msm_serial 78b0000.serial: msm_serial: detected port #0
[    2.572210] msm_serial 78b0000.serial: uartclk = 7372800
[    2.572423] 78b0000.serial: ttyMSM0 at MMIO 0x78b0000 (irq = 10,
base_baud = 460800) is a MSM
[    2.572508] BUG: spinlock bad magic on CPU#3, swapper/0/1
[    2.572534]  lock: msm_uart_ports+0x0/0x7e0, .magic: 00000000,
.owner: <none>/-1, .owner_cpu: 0
[    2.572552] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.6.0 #1
[    2.572565] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
[    2.572578] Call trace:
[    2.572594]  dump_backtrace+0x0/0x1e0
[    2.572609]  show_stack+0x24/0x30
[    2.572627]  dump_stack+0xe8/0x150
[    2.572643]  spin_dump+0x84/0xb8
[    2.572658]  do_raw_spin_lock+0xf8/0x120
[    2.572675]  _raw_spin_lock_irqsave+0x68/0x80
[    2.572692]  uart_add_one_port+0x3ac/0x4e8
[    2.572709]  msm_serial_probe+0x168/0x208
[    2.572725]  platform_drv_probe+0x58/0xa8
[    2.572739]  really_probe+0x290/0x498
[    2.572754]  driver_probe_device+0x12c/0x148
[    2.572768]  device_driver_attach+0x74/0x98
[    2.572782]  __driver_attach+0xc4/0x178
[    2.572798]  bus_for_each_dev+0x84/0xd8
[    2.572811]  driver_attach+0x30/0x40
[    2.572827]  bus_add_driver+0x170/0x258
[    2.572841]  driver_register+0x64/0x118
[    2.572856]  __platform_driver_register+0x54/0x60
[    2.572872]  msm_serial_init+0x40/0x70
[    2.572887]  do_one_initcall+0x94/0x460
[    2.572904]  kernel_init_freeable+0x274/0x2dc
[    2.572920]  kernel_init+0x18/0x110
[    2.572936]  ret_from_fork+0x10/0x18
[    2.572966] msm_serial: console setup on port #0
[    3.664259] printk: console [ttyMSM0] enabled

Full test log,
https://lkft.validation.linaro.org/scheduler/job/1361080#L3679
https://lkft.validation.linaro.org/scheduler/job/1361079#L3730

metadata:
  git branch: master
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
  kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/dragonboard-410c/lkft/linux-mainline/2607/config
dtb:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/dragonboard-410c/lkft/linux-mainline/2607/Image.gz--5.6+git0+b753101a4a-r0-apq8016-sbc-20200412114028-2607.dtb

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https://lkft.linaro.org