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Re: [PATCH][DEBUG] x86/refcount: split up refcount saturation handling

From Ingo Molnar <mingo@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH][DEBUG] x86/refcount: split up refcount saturation handling
Date 2017-09-02 12:40 +0200
Message-ID <ule0h-1NH-5@gated-at.bofh.it> (permalink)
References <ukDk5-1mJ-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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* Kees Cook <keescook@chromium.org> wrote:

> In support of debugging the problems Mike Galbraith has seen with
> x86-refcount vs gcc vs network refcounts...
> 
> This minimizes the differences between unchecked-refcount and x86-refcount
> by changing the refcount_dec() failure case to not saturate. The reporting
> of negative values is reduced to pr_warn from WARN to avoid spamming dmesg
> (which may impact race conditions). Ratelimiting is disabled just to be
> sure no reports are being dropped.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/x86/mm/extable.c | 51 ++++++++++++++++++++++++++++++++++-----------------
>  kernel/panic.c        |  2 +-
>  2 files changed, 35 insertions(+), 18 deletions(-)

If this patch is still useful then please include it in your next refcount series. 
Better debuggability is always welcome.

Thanks,

	Ingo

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Thread

[PATCH][DEBUG] x86/refcount: split up refcount saturation handling Kees Cook <keescook@chromium.org> - 2017-08-31 21:30 +0200
  Re: [PATCH][DEBUG] x86/refcount: split up refcount saturation  handling Ingo Molnar <mingo@kernel.org> - 2017-09-02 12:40 +0200
    Re: [PATCH][DEBUG] x86/refcount: split up refcount saturation handling Kees Cook <keescook@chromium.org> - 2017-09-02 22:00 +0200

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