linux-kernel - Re: [RFC V2] printk: add warning while drop partial text in msg

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] [day] [month] [year] [list]

Message-ID: <20171018010718.GA775@jagdpanzerIV>
Date:   Wed, 18 Oct 2017 10:07:18 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     pierre kuo <vichy.kuo@...il.com>
Cc:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        rostedt@...dmis.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC V2] printk: add warning while drop partial text in msg

On (10/18/17 01:10), pierre kuo wrote:
[..]
> > Well, it might get quite complicated, see printk_safe_flush_buffer().
> 
> BTW,  after checking printk_safe_flush_buffer() and related functions,
> we have one question:
> a) Why in printk_safe_log_store(), we need to use  atomic_xxxx operation in it?

because IRQ flush work iterates all CPUs and modifies CPUs' buffer state,
and this easily can race with printk_safe() or printk_nmi() on some of the
CPUs.

	-ss