Re: [PATCH v3 31/51] x86/dumpstack: allow preemption in show_stack_log_lvl() and dump_trace()

From: Josh Poimboeuf
Date: Mon Aug 15 2016 - 11:32:45 EST


On Sun, Aug 14, 2016 at 12:45:35AM -0700, Andy Lutomirski wrote:
> On Fri, Aug 12, 2016 at 7:28 AM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> > show_stack_log_lvl() and dump_trace() are already preemption safe:
> >
> > - If they're running in interrupt context, preemption is already
> > disabled and the percpu irq stack pointers can be trusted.
>
> I agree with the patch, but I have a minor nitpick about the
> description. The "irq stack" is an actual thing, but the relevant
> stacks here aren't just the irq stack: they're the irq stack, the IST
> stacks (on 64-bit), and the NMI stack (on 32-bit). The same logic
> applies, though.

Yeah. Maybe I'll just remove the "irq" qualifier and instead call them
"percpu stack pointers".

--
Josh