Re: [PATCH] powerpc/entry: Use hard_irq_disable() in arch_interrupt_exit_prepare()

[Venkat Rao Bagalkote <venkat88@linux.ibm.com>]

On 15/08/26 10:27 am, Mukesh Kumar Chaurasiya wrote:
> On Fri, Aug 14, 2026 at 11:42:22AM +0530, Mukesh Kumar Chaurasiya wrote:
>> On Fri, Aug 14, 2026 at 11:06:43AM +0530, Shrikanth Hegde wrote:
>> [...]
>>> This is good explanation, but what i not understanding is,
>>>
>>> why pattern of setting PACA_IRQ_HARD_DIS changed?
>>> Previous code at interrupt_exit_kernel_prepare which did local_irq_disable too.
>>>
>>> Please check where was PACA_IRQ_HARD_DIS set without GENERIC_ENTRY which was preventing
>>> this from happening?
>> That's an excellent point. I think we are looking at this incorrectly,
>> If this is related to the nested soft replay interrupt than this whole
>> dynamics changes, local_irq_disable will work for the actual interrupt
>> but when we go nested something is telling that the nested interrupt
>> that interrupts are enabled. Let me look at this more deeply.
>>
>> Regards,
>> Mukesh
> Hey Venkat,
>
> Can you try this diff,
>
> diff --git a/arch/powerpc/kernel/irq_64.c b/arch/powerpc/kernel/irq_64.c
> index d5c48d1b0a31..2fbfebef74fe 100644
> --- a/arch/powerpc/kernel/irq_64.c
> +++ b/arch/powerpc/kernel/irq_64.c
> @@ -117,7 +117,7 @@ static __no_kcsan void __replay_soft_interrupts(void)
>   	local_paca->irq_happened |= PACA_IRQ_REPLAYING;
>   
>   	ppc_save_regs(&regs);
> -	regs.softe = IRQS_ENABLED;
> +	regs.softe = IRQS_DISABLED;
>   	regs.msr |= MSR_EE;
>   
>   	/*
>
Hello Mukesh,

With the proposed change, I still the issue.

[    0.742633] ------------[ cut here ]------------
[    0.742633] WARNING: arch/powerpc/kernel/irq_64.c:75 at 
__replay_soft_interrupts+0x104/0x220, CPU#6: swapper/0/1
[    0.742637] Modules linked in:
[    0.742638] CPU: 6 UID: 0 PID: 1 Comm: swapper/0 Tainted: G   W      
      7.2.0-rc7-dirty #25 PREEMPT
[    0.742639] Tainted: [W]=WARN
[    0.742640] Hardware name: IBM,9080-HEX Power11 (architected) 
0x820200 0xf000007 of:IBM,FW1110.01 (NH1110_069) hv:phyp pSeries
[    0.742641] NIP:  c00000000003a384 LR: c00000000003a360 CTR: 
c000000000029f00
[    0.742642] REGS: c000000009757410 TRAP: 0700   Tainted: G W          
   (7.2.0-rc7-dirty)
[    0.742643] MSR:  8000000002021033 <SF,VEC,ME,IR,DR,RI,LE> CR: 
88024824  XER: 00000003
[    0.742646] CFAR: c00000000002a708 IRQMASK: 1
[    0.742646] GPR00: c00000000003a360 c0000000097576b0 c000000001b28100 
c0000000097576d8
[    0.742646] GPR04: 0000000000000000 0000000000000001 c00000000968d200 
c0000000096eb200
[    0.742646] GPR08: 0000000000000001 0000000000000041 0000000000000001 
000000002c1b8100
[    0.742646] GPR12: c000000000029f00 c0000005ffff8f00 0000000000000000 
c00000000968d200
[    0.742646] GPR16: c000000002f3aaf8 0000000000000000 c00000000284e138 
0000000000000000
[    0.742646] GPR20: c00000000303aaf8 c00000000303ade8 0000000000000001 
0000000000000000
[    0.742646] GPR24: c00000000303ae08 0000000000000000 0000000000000000 
0000000000000002
[    0.742646] GPR28: 0000000000000003 fcffffffffffffff fcffffffffffffff 
c00000000968d200
[    0.742662] NIP [c00000000003a384] __replay_soft_interrupts+0x104/0x220
[    0.742665] LR [c00000000003a360] __replay_soft_interrupts+0xe0/0x220
[    0.742668] Call Trace:
[    0.742668] [c0000000097576b0] [c00000000003a360] 
__replay_soft_interrupts+0xe0/0x220 (unreliable)
[    0.742672] [c000000009757860] [c00000000003a694] 
arch_local_irq_restore+0x1f4/0x2d8
[    0.742675] [c0000000097578b0] [c0000000002face0] 
console_flush_all+0x3ec/0x558
[    0.742676] [c000000009757a00] [c0000000002faee4] 
console_unlock+0x98/0x1d8
[    0.742678] [c000000009757a80] [c0000000002fc698] 
vprintk_emit+0x2c0/0x3f4
[    0.742680] [c000000009757af0] [c0000000002fdc70] vprintk+0x30/0x7c
[    0.742682] [c000000009757b10] [c0000000002f6c78] _printk+0x3c/0x50
[    0.742683] [c000000009757b30] [c00000000205d814] 
load_system_certificate_list+0x24/0x5c
[    0.742685] [c000000009757b90] [c00000000001111c] 
do_one_initcall+0x5c/0x3f0
[    0.742687] [c000000009757c70] [c00000000200684c] 
do_initcalls+0x11c/0x270
[    0.742689] [c000000009757d30] [c000000002006c78] 
kernel_init_freeable+0x228/0x3c0
[    0.742690] [c000000009757de0] [c000000000011600] kernel_init+0x30/0x260

[    0.742692] [c000000009757e50] [c00000000000df7c] 
ret_from_kernel_user_thread+0x14/0x1c


Regards,

Venkat.