[PATCH v3] irqchip/riscv-aplic: fix asynchronous probing

Tue Oct 13 08:27:27 PDT 2026

On 2026-10-12 12:12:59 [+0300], Vladimir Kondratiev wrote:
> boolean flag don't protect from race when probing several instances
> asynchronously. On system with multiple APLICs, if probed asynchronously,
> warning triggered as below.

Why is this async? Doesn't __platform_driver_probe() set it to sync?

> [    0.227210] riscv-aplic 67560000.interrupt-controller: 257 interrupts directly connected to 8 CPUs
> [    0.227210] riscv-aplic 674e0000.interrupt-controller: 257 interrupts directly connected to 8 CPUs
> [    0.227224] ------------[ cut here ]------------
> [    0.227227] list_add double add: new=ffffffff8130ced0, prev=ffffffff8130ced0, next=ffffffff81316d40.
> [    0.227302] WARNING: lib/list_debug.c:35 at __list_add_valid_or_report+0xe0/0xe6, CPU#4: kworker/u97:0/211
> [    0.227322] Modules linked in:
> [    0.227333] CPU: 4 UID: 0 PID: 211 Comm: kworker/u97:0 Not tainted 7.3.0-rc6 #1 PREEMPT_RT
> [    0.227341] Hardware name: EyeQ7H evaluation board (DT)
> [    0.227346] Workqueue: async async_run_entry_fn
> [    0.227358] epc : __list_add_valid_or_report+0xe0/0xe6
> [    0.227366]  ra : __list_add_valid_or_report+0xe0/0xe6
> [    0.227375] epc : ffffffff804a08a0 ra : ffffffff804a08a0 sp : ffffffc600823b90
> [    0.227379]  gp : ffffffff81389e70 tp : ffffffd60135ee00 t0 : 0000000000000000
> [    0.227383]  t1 : 3fffffffffffffff t2 : 0000000000000000 s0 : ffffffc600823bb0
> [    0.227387]  s1 : ffffffff8130ced0 a0 : 0000000000000058 a1 : ffffffd9efc9e5c0
> [    0.227391]  a2 : ffffffd9efd5c510 a3 : 0000000000000000 a4 : 0000000000000000
> [    0.227395]  a5 : 0000000000000000 a6 : ffffffd9efc6e5c0 a7 : bfffffffffffe000
> [    0.227399]  s2 : 0000000000000000 s3 : ffffffff8130ce28 s4 : 0000000000000000
> [    0.227402]  s5 : ffffffd6018b65c8 s6 : 0000000000000000 s7 : ffffffd6012fd605
> [    0.227406]  s8 : ffffffd6010c3400 s9 : 0000000000000000 s10: 0000000000000000
> [    0.227409]  s11: 0000000000000000 t3 : 3fffffffffffe000 t4 : 0000000000000020
> [    0.227413]  t5 : 0000000000000000 t6 : ffffffc6008238f8 ssp : 0000000000000000
> [    0.227417] status: 0000000200000120 badaddr: ffffffff804a08a0 cause: 0000000000000003
> [    0.227422] [<ffffffff804a08a0>] __list_add_valid_or_report+0xe0/0xe6
> [    0.227432] [<ffffffff80558226>] register_syscore+0x30/0x60
> [    0.227444] [<ffffffff804ca0fe>] aplic_probe+0xd2/0xfa
> [    0.227453] [<ffffffff80559b2e>] platform_probe+0x3e/0x7a
> [    0.227461] [<ffffffff8055731a>] really_probe+0x88/0x35c
> [    0.227469] [<ffffffff805576ae>] __driver_probe_device+0xc0/0x13a
> [    0.227478] [<ffffffff805577f4>] driver_probe_device+0x38/0xb2
> [    0.227486] [<ffffffff80557ba6>] __driver_attach_async_helper+0x3c/0xc4
> [    0.227493] [<ffffffff80054a0e>] async_run_entry_fn+0x28/0x154
> [    0.227500] [<ffffffff8004482a>] process_one_work+0x14e/0x3d2
> [    0.227509] [<ffffffff800452fe>] worker_thread+0x144/0x286
> [    0.227516] [<ffffffff8004ca3e>] kthread+0xee/0x10e
> [    0.227524] [<ffffffff8001050a>] ret_from_fork_kernel+0x18/0x14e
> [    0.227532] [<ffffffff807bef36>] ret_from_fork_kernel_asm+0x16/0x18
> [    0.227542] ---[ end trace 0000000000000000 ]---
> [    0.228475] pinctrl-single 48508000.pinctrl: 512 pins, size 2048
> [    0.228500] pinctrl-single 53838000.pinctrl: 512 pins, size 2048
> [    0.228723] pinctrl-single 67107000.pinctrl: 512 pins, size 2048
> [    0.227210] riscv-aplic 674e0000.interrupt-controller: 257 interrupts directly connected to 8 CPUs
> [    0.227224] ------------[ cut here ]------------
> [    0.227227] list_add double add: new=ffffffff8130ced0, prev=ffffffff8130ced0, next=ffffffff81316d40.
> [    0.227302] WARNING: lib/list_debug.c:35 at __list_add_valid_or_report+0xe0/0xe6, CPU#4: kworker/u97:0/211
> [    0.227322] Modules linked in:
> [    0.227333] CPU: 4 UID: 0 PID: 211 Comm: kworker/u97:0 Not tainted 7.3.0-rc6 #1 PREEMPT_RT
> [    0.227341] Hardware name: EyeQ7H evaluation board (DT)
> [    0.227346] Workqueue: async async_run_entry_fn
> [    0.227358] epc : __list_add_valid_or_report+0xe0/0xe6
> [    0.227366]  ra : __list_add_valid_or_report+0xe0/0xe6
> [    0.227375] epc : ffffffff804a08a0 ra : ffffffff804a08a0 sp : ffffffc600823b90
> [    0.227379]  gp : ffffffff81389e70 tp : ffffffd60135ee00 t0 : 0000000000000000
> [    0.227383]  t1 : 3fffffffffffffff t2 : 0000000000000000 s0 : ffffffc600823bb0
> [    0.227387]  s1 : ffffffff8130ced0 a0 : 0000000000000058 a1 : ffffffd9efc9e5c0
> [    0.227391]  a2 : ffffffd9efd5c510 a3 : 0000000000000000 a4 : 0000000000000000
> [    0.227395]  a5 : 0000000000000000 a6 : ffffffd9efc6e5c0 a7 : bfffffffffffe000
> [    0.227399]  s2 : 0000000000000000 s3 : ffffffff8130ce28 s4 : 0000000000000000
> [    0.227402]  s5 : ffffffd6018b65c8 s6 : 0000000000000000 s7 : ffffffd6012fd605
> [    0.227406]  s8 : ffffffd6010c3400 s9 : 0000000000000000 s10: 0000000000000000
> [    0.227409]  s11: 0000000000000000 t3 : 3fffffffffffe000 t4 : 0000000000000020
> [    0.227413]  t5 : 0000000000000000 t6 : ffffffc6008238f8 ssp : 0000000000000000
> [    0.227417] status: 0000000200000120 badaddr: ffffffff804a08a0 cause: 0000000000000003
> [    0.227422] [<ffffffff804a08a0>] __list_add_valid_or_report+0xe0/0xe6
> [    0.227432] [<ffffffff80558226>] register_syscore+0x30/0x60
> [    0.227444] [<ffffffff804ca0fe>] aplic_probe+0xd2/0xfa
> [    0.227453] [<ffffffff80559b2e>] platform_probe+0x3e/0x7a
> [    0.227461] [<ffffffff8055731a>] really_probe+0x88/0x35c
> [    0.227469] [<ffffffff805576ae>] __driver_probe_device+0xc0/0x13a
> [    0.227478] [<ffffffff805577f4>] driver_probe_device+0x38/0xb2
> [    0.227486] [<ffffffff80557ba6>] __driver_attach_async_helper+0x3c/0xc4
> [    0.227493] [<ffffffff80054a0e>] async_run_entry_fn+0x28/0x154
> [    0.227500] [<ffffffff8004482a>] process_one_work+0x14e/0x3d2
> [    0.227509] [<ffffffff800452fe>] worker_thread+0x144/0x286
> [    0.227516] [<ffffffff8004ca3e>] kthread+0xee/0x10e
> [    0.227524] [<ffffffff8001050a>] ret_from_fork_kernel+0x18/0x14e
> [    0.227532] [<ffffffff807bef36>] ret_from_fork_kernel_asm+0x16/0x18
> [    0.227542] ---[ end trace 0000000000000000 ]---

Would you mind providing a coherent description of the problem and
implemented solution instead of slapping console output?

> Fixes: b330fbfd34d7 ("irqchip/riscv-aplic: Register syscore operations only once")
> Signed-off-by: Vladimir Kondratiev <vladimir.kondratiev at mobileye.com>
> ---
> Changes in v3:
> - drop __ro_after_init attribute due to write to read-only page concern

What concern? That __ro_after_init can stay. It is built-in only.

> diff --git a/drivers/irqchip/irq-riscv-aplic-main.c b/drivers/irqchip/irq-riscv-aplic-main.c
> index d9afb6ae98cf56d6fd9f858c31a3d23546c3b450..54e1d5602f15a04127e900c0a4983022d49da553 100644
> --- a/drivers/irqchip/irq-riscv-aplic-main.c
> +++ b/drivers/irqchip/irq-riscv-aplic-main.c
> @@ -116,14 +116,12 @@ static struct syscore aplic_syscore = {
>  	.ops = &aplic_syscore_ops,
>  };
>  
> -static bool aplic_syscore_registered __ro_after_init;
> +static atomic_t aplic_syscore_registered = ATOMIC_INIT(0);
>  
>  static void aplic_syscore_init(void)
>  {
> -	if (!aplic_syscore_registered) {
> +	if (!atomic_cmpxchg(&aplic_syscore_registered, 0, 1))
>  		register_syscore(&aplic_syscore);
> -		aplic_syscore_registered = true;
> -	}
>  }
>  
>  static int aplic_pm_notifier(struct notifier_block *nb, unsigned long action, void *data)
> 

Sebastian