On Mon, 8 Oct 2018 17:39:11 +0200 Christophe LEROY <christophe.le...@c-s.fr> wrote:
> Hi Nick, > > Le 19/07/2017 à 08:59, Nicholas Piggin a écrit : > > Use nmi_enter similarly to system reset interrupts. This uses NMI > > printk NMI buffers and turns off various debugging facilities that > > helps avoid tripping on ourselves or other CPUs. > > > > Signed-off-by: Nicholas Piggin <npig...@gmail.com> > > --- > > arch/powerpc/kernel/traps.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > > index 2849c4f50324..6d31f9d7c333 100644 > > --- a/arch/powerpc/kernel/traps.c > > +++ b/arch/powerpc/kernel/traps.c > > @@ -789,8 +789,10 @@ int machine_check_generic(struct pt_regs *regs) > > > > void machine_check_exception(struct pt_regs *regs) > > { > > - enum ctx_state prev_state = exception_enter(); > > int recover = 0; > > + bool nested = in_nmi(); > > + if (!nested) > > + nmi_enter(); > > This alters preempt_count, then when die() is called > in_interrupt() returns true allthough the trap didn't happen in > interrupt, so oops_end() panics for "fatal exception in interrupt" > instead of gently sending SIGBUS the faulting app. Thanks for tracking that down. > Any idea on how to fix this ? I would say we have to deliver the sigbus by hand. if ((user_mode(regs))) _exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip); else die("Machine check", regs, SIGBUS);