Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   John Ogness <john.ogness@linutronix.de>
To:     Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Petr Mladek <pmladek@suse.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] printk: fix buffer overflow potential for print_text()
In-Reply-To: <YAYriDiAl7lajty9@jagdpanzerIV.localdomain>
References: <20210114170412.4819-1-john.ogness@linutronix.de> <YAGE1O/nG57hyRs4@alley> <YAGFebfPNLwjyhcl@alley> <YAYriDiAl7lajty9@jagdpanzerIV.localdomain>
Date:   Tue, 19 Jan 2021 10:00:47 +0106
Message-ID: <87r1mh5mso.fsf@jogness.linutronix.de>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On 2021-01-19, Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote:
> John, how did you spot these problems?

I am preparing my series to remove the logbuf_lock, which also refactors
and consolidates code from syslog_print_all() and
kmsg_dump_get_buffer(). While testing/verifying my series, I noticed the
these oddities in the semantics and decided I should research where they
came from and if they were actually necessary.

I wouldn't say the oddities are necessary (in fact, they are quite
annoying), but we have decided to keep them in out of fear of breaking
out-of-tree modules and/or interesting userspace code.

One positive effect of the rework is that we are finding these oddities
and documenting them. I think you and Petr are going down a similar path
with the console registration stuff now.

John