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

From: Jiaxun Yang
Date: Fri Aug 02 2024 - 05:44:16 EST




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