Re: [PATCH] powerpc: Restore kuap regs during syscall restart exit

[Mukesh Kumar Chaurasiya]

On Mon, Jun 15, 2026 at 10:51:43AM +0530, Shrikanth Hegde wrote:
> Hi Mukesh.
> 
> On 6/13/26 6:08 PM, Mukesh Kumar Chaurasiya (IBM) wrote:
> > During syscall restart, we block the kuap as we need to replay
> > interrupts. Which are not restored when we exit to the user, hence we
> > get a fault which ends up with `bad_access_pkey` and hence crashing the
> > kernel.
> > 
> > We have already stored the kuap values during the entry, just restore
> > them when we exit.
> > 
> > Applies on linux-next (next-20260610).
> > 
> 
> Please re-write the changelog in imperative mood.
> i.e Avoid we/you/I.
> 
> https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#describe-your-changes
> 
> 
> > Fixes: bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY feature")
> > Reported-by: Sayali Patil <sayalip@xxxxxxxxxxxxx>
> > Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@xxxxxxxxx>
> > ---
> >   arch/powerpc/kernel/interrupt.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
> > index 89a999be1352..159901d6ba8c 100644
> > --- a/arch/powerpc/kernel/interrupt.c
> > +++ b/arch/powerpc/kernel/interrupt.c
> > @@ -165,7 +165,7 @@ notrace unsigned long syscall_exit_restart(unsigned long r3, struct pt_regs *reg
> >   		local_irq_disable();
> >   		goto again;
> >   	}
> > -
> > +	kuap_user_restore(regs);
> 
> Please describe where was kuap save was done in the stack.
> 
> >   	regs->exit_result |= regs->exit_flags;
> >   	return regs->exit_result;
> 
Sent out V2 with the requested changes.

Regards,
Mukesh