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Date:   Thu, 30 Sep 2021 11:36:26 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Alexander Popov <alex.popov@linux.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Paul McKenney <paulmck@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Joerg Roedel <jroedel@suse.de>,
        Maciej Rozycki <macro@orcam.me.uk>,
        Muchun Song <songmuchun@bytedance.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Petr Mladek <pmladek@suse.com>,
        Luis Chamberlain <mcgrof@kernel.org>, Wei Liu <wl@xen.org>,
        John Ogness <john.ogness@linutronix.de>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
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Subject: Re: [PATCH] Introduce the pkill_on_warn boot parameter
Message-ID: <202109301132.E29DB764E8@keescook>
References: <20210929185823.499268-1-alex.popov@linux.com>
 <d290202d-a72d-0821-9edf-efbecf6f6cef@linux.com>
 <20210929163143.aa8b70ac9d5cf0b628823370@linux-foundation.org>
 <de96ffec-bbd8-2724-9285-0867cd9a08a0@linux.com>
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On Thu, Sep 30, 2021 at 09:27:43PM +0300, Alexander Popov wrote:
> On 30.09.2021 02:31, Andrew Morton wrote:
> > On Wed, 29 Sep 2021 22:01:33 +0300 Alexander Popov <alex.popov@linux.com> wrote:
> > 
> >> On 29.09.2021 21:58, Alexander Popov wrote:
> >> [...]
> >> If you are fine with this approach, I will prepare a patch adding the
> >> pkill_on_warn sysctl.
> > 
> > Why do we need a boot parameter?  Isn't a sysctl all we need for this
> > feature? 
> 
> I would say we need both sysctl and boot parameter for pkill_on_warn.
> That would be consistent with panic_on_warn, ftrace_dump_on_oops and
> oops/panic_on_oops.

If you want to change it at runtime, just make a sysctl: it will
be available as a bootparam since v5.8. See commit 3db978d480e2
("kernel/sysctl: support setting sysctl parameters from kernel command
line")

-- 
Kees Cook