Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Thu, 21 Feb 2019 09:36:25 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        stable@vger.kernel.org, Changbin Du <changbin.du@gmail.com>
Subject: Re: [PATCH 1/2 v2] kprobe: Do not use uaccess functions to access
 kernel memory that can fault
Message-ID: <20190221093625.56afccd2@gandalf.local.home>
In-Reply-To: <20190221165252.4a9033b3348f30f9d973dbc4@kernel.org>
References: <20190215174712.372898450@goodmis.org>
        <20190215174945.557218316@goodmis.org>
        <20190221165252.4a9033b3348f30f9d973dbc4@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 21 Feb 2019 16:52:52 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Basically OK to me.
> Could you use probe_kernel_read() in this context, since probe_mem_read() is a
> wrapper function for template code.
> 
> With that change,
> 
> Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

This already hit Linus's tree. I was able to reproduce the crash, so I
streamlined it. I should have still pushed more for your ack first.
Sorry about that.

For some reason, I thought the change was in the generic probe code,
and accepted the probe_mem_read(). Anyway, did you want to send a patch
to change it to probe_kernel_read(), for the merge window?

> 
> And for the long term, I need to find more efficient (or smarter) way to do it,
> like strnlen_user() does.

Agreed.

Thanks,

-- Steve