linux-kernel - Re: [PATCH 1/1] mm: sysctl: add panic_on_inconsistent

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1cb86d36-7620-be11-7833-0b3bab3c5c1f@suse.cz>
Date:   Mon, 3 Feb 2020 13:19:29 +0100
From:   Vlastimil Babka <vbabka@...e.cz>
To:     Kees Cook <keescook@...omium.org>
Cc:     Grzegorz Halat <ghalat@...hat.com>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
        linux-doc@...r.kernel.org, ssaner@...hat.com, atomlin@...hat.com,
        oleksandr@...hat.com, vbendel@...hat.com, kirill@...temov.name,
        khlebnikov@...dex-team.ru, borntraeger@...ibm.com,
        Andrew Morton <akpm@...ux-foundation.org>,
        Iurii Zaikin <yzaikin@...gle.com>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
        Qian Cai <cai@....pw>
Subject: Re: [PATCH 1/1] mm: sysctl: add panic_on_inconsistent_mm sysctl

On 1/30/20 8:28 PM, Kees Cook wrote:
> On Thu, Jan 30, 2020 at 03:44:50PM +0100, Vlastimil Babka wrote:
>> On 1/29/20 7:08 PM, Grzegorz Halat wrote:
>>> 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.
>>>
>>> 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 of
>>> a new sysctl.
>>>
>>> Add a new sysctl - panic_on_inconsistent_mm. 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).
>>
>> I wonder, should enabling the sysctl also effectively convert VM_WARN...
>> to VM_BUG... ?
> 
> There is already panic_on_warn sysctl... wouldn't that be sufficient?

True, forgot about it. Thanks.