Re: [PATCH] ARM: enable interrupts when arm_notify_die() is handling user mode errors

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 2026-06-25 11:20:13 [+0100], Russell King wrote:
> > is not worth doing it? With this I can my little testcase working.
> 
> No, it isn't, because if you enable PERF_EVENTS then BKPT breaks.
> hw_breakpoint.c claims this vector.

I see.

…
> BKPT is a total mess.

Understood.

> > it does cond_local_irq_enable() which enables the interrupts if they
> > were enabled by the "caller", sends the signal (SIGTRAP).
> 
> I'm happy with that approach as far as interrupts go, but we can't
> change the behaviour for FSR=2 again, beyond fixing LinusW's
> commit (which has recently been reported as a regression.)
> 
> Note that the change which makes this raise a SIGTRAP rather than
> SIGBUS when PERF_EVENTS=y could _also_ be reported as a regression
> that we would have to fix, and making FSR=2 raise a SIGTRAP now
> could very well invite that regression to be reported.
> 
> Essentially, I don't think we can "fix" BKPT to always raise SIGTRAP.
> The BKPT instruction is something the kernel has never _officially_
> supported.

It looked like an easy fix. You explained that it is a bigger mess with
"other features" and so on. Given that and the fact that it was never
supported, I would appreciate just to enable interrupts before the
(SIGBUS) signal is sent.

Sebastian