linux-kernel - Re: [RFC][PATCH 1/2] printk: lock console_sem before we unregister boot consoles

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]

Date:   Thu, 25 Apr 2019 16:56:06 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [RFC][PATCH 1/2] printk: lock console_sem before we unregister
 boot consoles

On (04/25/19 09:50), Petr Mladek wrote:
> > Sure we can.
> > 
> > We also can take extra care of pr_info("%sconsole [%s%d] enabled\n".
> > Right now we do
> > 
> > 	...
> > 	console_unlock();
> > 	console_sysfs_notify();
> > 
> > 	pr_info("%sconsole [%s%d] enabled\n",....
> > 
> > 
> > But we can simply move that pr_info() a bit up:
> > 
> > 	pr_info("%sconsole [%s%d] enabled\n",
> > 	console_unlock();
> > 	console_sysfs_notify();
> > 
> > 
> > So the message will be printed on all consoles.
> 
> Great idea!
> 
> It would deserve a separate patch that moves the pr_info()
> and removes the invalid comment.
> 
> Actually, the pr_info() would deserve a comment explaining
> why it should be called before console_unlock().

Good. So I think I'll drop patch #1 from the series, add
two more patches - invalid comment + pr_info() - and rework
locking in patch #3 (this should take care of a race which
patch #1 was intended to fix).

	-ss