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;
Date:   Tue, 2 Mar 2021 09:08:11 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Vlastimil Babka <vbabka@suse.cz>, Petr Mladek <pmladek@suse.com>,
        Marco Elver <elver@google.com>, Timur Tabi <timur@kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        roman.fietze@magna.com, Kees Cook <keescook@chromium.org>,
        John Ogness <john.ogness@linutronix.de>,
        Akinobu Mita <akinobu.mita@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Pavel Machek <pavel@ucw.cz>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH 3/3] [v4] lib/vsprintf: no_hash_pointers prints all
 addresses as unhashed
Message-ID: <20210302090811.620ae7d0@gandalf.local.home>
In-Reply-To: <CAMuHMdUB4DZxHo=j1+EsSsoGCdWmDO9mBo0cUtAH4OYHy3sBzw@mail.gmail.com>
References: <20210214161348.369023-1-timur@kernel.org>
        <20210214161348.369023-4-timur@kernel.org>
        <CAMuHMdULKZCJevVJcp7TxzLdWLjsQPhE8hqxhnztNi9bjT_cEw@mail.gmail.com>
        <CANpmjNNm-4s16_KQ1_NqFN4XOESJh4_=33LHQzt+p4V0Cy=Xzw@mail.gmail.com>
        <CAMuHMdWWsZ-vTGZCeLtcwLTuBYpeP0STfhrK37wiwmyfsQ798A@mail.gmail.com>
        <YD49x/UGUq6MSE39@alley>
        <8893ff08-1e50-316c-f632-cd37be1690d5@suse.cz>
        <CAMuHMdUB4DZxHo=j1+EsSsoGCdWmDO9mBo0cUtAH4OYHy3sBzw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Tue, 2 Mar 2021 14:49:42 +0100
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> > So this is basically a kernel tinyfication issue, right? Is that still pursued
> > today? Are there better config options suitable for this than CONFIG_DEBUG_KERNEL?  
> 
> As long as I hear about products running Linux on SoCs with 10 MiB of
> SRAM, I think the answer is yes.
> I'm not immediately aware of a better config option.  There are no more
> TINY options left, and EXPERT selects DEBUG_KERNEL.

Since the trace_printk() uses the same type of notice, I wonder if we could
make this into a helper function and just pass in the top part.

+	pr_warn("**********************************************************\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**                                                      **\n");


+	pr_warn("** This system shows unhashed kernel memory addresses   **\n");
+	pr_warn("** via the console, logs, and other interfaces. This    **\n");
+	pr_warn("** might reduce the security of your system.            **\n");

Only the above section is really unique. The rest can be a boiler plate.

-- Steve

+	pr_warn("**                                                      **\n");
+	pr_warn("** If you see this message and you are not debugging    **\n");
+	pr_warn("** the kernel, report this immediately to your system   **\n");
+	pr_warn("** administrator!                                       **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**********************************************************\n");
+