linux-kernel - Re: [PATCH] kprobes, x86/alternatives: use text_mutex to protect smp_alt

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: <20171027111527.GD1305@nazgul.tnic>
Date:   Fri, 27 Oct 2017 13:15:27 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Zhou Chengming <zhouchengming1@...wei.com>
Cc:     mhiramat@...nel.org, ananth@...ux.vnet.ibm.com,
        anil.s.keshavamurthy@...el.com, davem@...emloft.net, hpa@...or.com,
        tglx@...utronix.de, peterz@...radead.org, jkosina@...e.cz,
        rostedt@...dmis.org, mjurczyk@...gle.com, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kprobes, x86/alternatives: use text_mutex to protect
 smp_alt_modules

On Fri, Oct 27, 2017 at 05:34:44PM +0800, Zhou Chengming wrote:
> Fixes: 2cfa197 "ftrace/alternatives: Introducing *_text_reserved
> functions"
> 
> We use alternatives_text_reserved() to check if the address is in
> the fixed pieces of alternative reserved, but the problem is that
> we don't hold the smp_alt mutex when call this function. So the list
> traversal may encounter a deleted list_head if another path is doing
> alternatives_smp_module_del().

Is this something you've triggered on a real machine or is this just
from code staring?

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--