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From: Ingo Molnar <mingo@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Mike Galbraith <efault@gmx.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][DEBUG] x86/refcount: split up refcount saturation handling
Date: Sat, 2 Sep 2017 12:35:00 +0200	[thread overview]
Message-ID: <20170902103459.chfpuomyyytmre52@gmail.com> (raw)
In-Reply-To: <20170831192728.GA135568@beast>


* 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

  reply	other threads:[~2017-09-02 10:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-31 19:27 [PATCH][DEBUG] x86/refcount: split up refcount saturation handling Kees Cook
2017-09-02 10:35 ` Ingo Molnar [this message]
2017-09-02 19:51   ` Kees Cook

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