Subject: Re: [PATCH 1/1] arm: traps: remove fp underflow checking

From: "Russell King (Oracle)" <[email-masked]>
Date: Fri, 24 Apr 2026 13:21:38 +0100

On Fri, Apr 24, 2026 at 10:00:29AM +0530, Maninder Singh wrote:
> with IRQSTACKS fp can point outside of thread's stack.
> And when there is crash reported from IRQ side, it always report
> "frame pointer underflow", which is not real underflow.
> 
> Unhandled fault: page domain fault (0x81b) at 0x00000000
> ..
> PC is at handle_irq_desc+0x68/0xa4
> LR is at generic_handle_domain_irq+0x18/0x1c
> ..
> 
> Call trace: frame pointer underflow
>  handle_irq_desc from generic_handle_domain_irq+0x18/0x1c
>  generic_handle_domain_irq from gic_handle_irq+0x78/0x8c
>  gic_handle_irq from generic_handle_arch_irq+0x3c/0x4c
> ..
> 
> It is just warning print and there is no decision based on this
> to stop backtrack or etc. So it can be removed.

Please find a way to check whether the frame pointer is within the
IRQ stack rather than removing this.

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!