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Re: [PATCH v5 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI

From Aaron Tomlin <atomlin@redhat.com>
Newsgroups linux.kernel
Subject Re: [PATCH v5 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI
Date 2016-04-14 17:30 +0200
Message-ID <rnRns-3WP-19@gated-at.bofh.it> (permalink)
References <rnRdM-3Ro-27@gated-at.bofh.it> <rnRns-3WP-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Tue 2016-04-05 13:26 -0400, 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>
> ---
>  arch/arm/kernel/smp.c | 9 ---------
>  lib/nmi_backtrace.c   | 9 +++++++++
>  2 files changed, 9 insertions(+), 9 deletions(-)

Thanks Chris.

Acked-by: Aaron Tomlin <atomlin@redhat.com>

-- 
Aaron Tomlin

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Re: [PATCH v5 2/4] nmi_backtrace: do a local dump_stack() instead of  a self-NMI Aaron Tomlin <atomlin@redhat.com> - 2016-04-14 17:30 +0200

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