linux-kernel - Re: [PATCH printk v5 1/1] printk: extend console

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:   Fri, 6 May 2022 09:55:05 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     Marek Szyprowski <m.szyprowski@...sung.com>,
        John Ogness <john.ogness@...utronix.de>,
        Petr Mladek <pmladek@...e.com>
Cc:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-amlogic@...ts.infradead.org
Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for per-console
 locking

Hi,

On 06/05/2022 08:43, Marek Szyprowski wrote:
> Hi John,
> 
> On 06.05.2022 00:33, John Ogness wrote:
>> On 2022-05-05, John Ogness <john.ogness@...utronix.de> wrote:
>>> I will go through and check if all access to AML_UART_CONTROL is
>>> protected by port->lock.
>> The startup() callback of the uart_ops is not called with the port
>> locked. I'm having difficulties identifying if the startup() callback
>> can occur after the console was already registered via meson_uart_init()
>> and could be actively printing, but I see other serial drivers are
>> protecting their registers in the startup() callback with the
>> port->lock.
>>
>> Could you try booting the meson hardware with the following change? (And
>> removing any previous debug changes I posted?)
> 
> Bingo! It looks that the startup() is called when getty initializes
> console. This fixed the issues observed on the Amlogic Meson based boards.
> 
> Feel free to add:
> 
> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
> 
> Best regards

Thanks all for figuring out the issue, perhaps other uart drivers could fall
in the same issue if startup code isn't protected with lock ?

Neil