Re: [RFC] MIPS: smp: Sleeping func called from start_secondary()

[Jiaxun Yang]

在2024年8月2日八月 下午4:45，Serge Semin写道：
> Hi folks,
>
> To debug some another problem I recently enabled the
> CONFIG_DEBUG_ATOMIC_SLEEP config for my SoC based on the 2xP5600 cores
> with MIPS GIC as IRQ-controller. That caused the next BUG backtrace
> started being printed to the system log during the device boot-up:

Hi Serge,

Thanks for reporting the problem!

I actually have a patch lying around somewhere to convert cevt-r4k to use CPUHP
interface and avoid requesting interrupt on secondary CPUs.

Will post after getting more platform tests.

Thanks
- Jiaxun

>
> [    0.118053] BUG: sleeping function called from invalid context at 
> kernel/locking/mutex.c:283
> [    0.118062] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 
> 0, name: swapper/1
> [    0.118069] preempt_count: 1, expected: 0
> [    0.118074] RCU nest depth: 0, expected: 0
> [    0.118078] Preemption disabled at:
> [    0.118082] [<80105040>] arch_dup_task_struct+0x20/0x118
> [    0.118116] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 
> 6.11.0-rc1-bt1-00312-gca6f9469050c-dirty #2460
> [    0.118134] Stack : 816d0000 801b89bc 81870000 00000004 a02d0c08 
> 00000000 84ae7dcc 801b84c0
> [    0.118167]         00000000 00000002 00000000 00000000 00000000 
> 00000001 84ae7d70 84aaf200
> [    0.118195]         00000000 00000000 81115acc 00000000 00000059 
> 84ae7bec 00000000 00000000
> [    0.118222]         00000000 ffffffff ffffffea 00000020 816d0000 
> 00000000 81115acc 00000002
> [    0.118250]         00000000 04240021 a02d0c08 00000000 00000000 
> 00000000 30400000 ac24242a
> [    0.118277]         ...
> [    0.118286] Call Trace:
> [    0.118289] [<8010af2c>] show_stack+0x88/0x120
> [    0.118309] [<80f09dfc>] dump_stack_lvl+0x78/0xb0
> [    0.118323] [<801778d0>] __might_resched+0x190/0x1f0
> [    0.118349] [<80f10f80>] mutex_lock+0x20/0x74
> [    0.118365] [<801c8590>] irq_create_mapping_affinity+0x48/0x104
> [    0.118390] [<801121ec>] r4k_clockevent_init+0x58/0x38c
> [    0.118402] [<80116658>] start_secondary+0x34/0x134
> [    0.118411] [<80f0b1e4>] smp_bootstrap+0x68/0x98
> [    0.118424] 
>
> I managed to investigate the problem a bit and the reason turned out to be
> in the irq_create_mapping() method eventually invoked in the framework of the
> secondary CPU start-up procedure. The more detailed calls chain is:
> start_secondary()
> +-> mips_clockevent_init()
>     +-> r4k_clockevent_init()
>         +-> get_c0_compare_int()
>             +-> gic_get_c0_compare_int()
>                 +-> irq_create_mapping()
>                     +-> irq_create_mapping_affinity()
>                         +-> mutex_lock()
>                             +-> might_sleep()
>                                 +-> might_resched()
>                                     +-> __might_resched()
>                                         +-> Print the log above
>
> I currently lack of free time for further investigation in an attempt to
> find a reasonable solution. So here is just a report and a short summary
> of the problem. Should you have any idea of how to fix the problem I'll be
> very glad to test it out on a short notice.
>
> -Serge(y)

-- 
- Jiaxun