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From:   Qian Cai <cai@lca.pw>
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Subject: Re: [PATCH 1/1] mm: sysctl: add panic_on_mm_error sysctl
Date:   Mon, 27 Jan 2020 07:26:21 -0500
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References: <20200127101100.92588-1-ghalat@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
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        Andrew Morton <akpm@linux-foundation.org>,
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        Kees Cook <keescook@chromium.org>,
        Luis Chamberlain <mcgrof@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>
In-Reply-To: <20200127101100.92588-1-ghalat@redhat.com>
To:     Grzegorz Halat <ghalat@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
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> On Jan 27, 2020, at 5:11 AM, Grzegorz Halat <ghalat@redhat.com> wrote:
>=20
> Memory management subsystem performs various checks at runtime,
> if an inconsistency is detected then such event is being logged and kernel=

> continues to run. While debugging such problems it is helpful to collect
> memory dump as early as possible. Currently, there is no easy way to panic=

> kernel when such error is detected.
>=20
> It was proposed[1] to panic the kernel if panic_on_oops is set but this
> approach was not accepted. One of alternative proposals was introduction o=
f
> a new sysctl.
>=20
> The patch adds panic_on_mm_error sysctl. If the sysctl is set then the
> kernel will be crashed when an inconsistency is detected by memory
> management. This currently means panic when bad page or bad PTE
> is detected(this may be extended to other places in MM).
>=20
> Another use case of this sysctl may be in security-wise environments,
> it may be more desired to crash machine than continue to run with
> potentially damaged data structures.

Well, on the other hand, this will allow a normal user to more easily crash t=
he system due to a recoverable bug which could result in local DoS.=