Re: [PATCH v7 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI

Petr Mladek
2016-08-09T12:37:40Z

On Mon 2016-08-08 12:03:36, Chris Metcalf wrote:
> Currently on arm there is code that checks whether it should call
> dump_stack() explicitly, to avoid trying to raise an NMI when the
> current context is not preemptible by the backtrace IPI. Similarly,
> the forthcoming arch/tile support uses an IPI mechanism that does
> not support generating an NMI to self.
>
> Accordingly, move the code that guards this case into the generic
> mechanism, and invoke it unconditionally whenever we want a
> backtrace of the current cpu. It seems plausible that in all cases,
> dump_stack() will generate better information than generating a
> stack from the NMI handler. The register state will be missing,
> but that state is likely not particularly helpful in any case.
>
> Or, if we think it is helpful, we should be capturing and emitting
> the current register state in all cases when regs == NULL is passed
> to nmi_cpu_backtrace().
>
> Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
> Acked-by: Aaron Tomlin <atomlin@redhat.com>

Sounds and looks fine to me.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr Mladek