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, 5 Jan 2021 12:10:16 +0000
From:   Daniel Thompson <daniel.thompson@linaro.org>
To:     bodefang <bodefang@126.com>
Cc:     jason.wessel@windriver.com, dianders@chromium.org, arnd@arndb.de,
        gregkh@linuxfoundation.org, kgdb-bugreport@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kgdbts: Passing ekgdbts to command line causes panic
Message-ID: <20210105121016.ritlzseyjprh5rhg@holly.lan>
References: <1609120738-202321-1-git-send-email-bodefang@126.com>
 <20210104112854.fghr32y37mzw6fpb@holly.lan>
 <279df92c.1b26.176d0907b64.Coremail.bodefang@126.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <279df92c.1b26.176d0907b64.Coremail.bodefang@126.com>
Precedence: bulk

Please avoid top posting. Threads on LKML are typically presented as
follows.

On Tue, Jan 05, 2021 at 11:21:38AM +0800, bodefang wrote:
> At 2021-01-04 19:28:54, "Daniel Thompson" <daniel.thompson@linaro.org>
> wrote:
> >On Mon, Dec 28, 2020 at 09:58:58AM +0800, Defang Bo wrote:
> >> Similar to commit<1bd54d851f50>("kgdboc: Passing ekgdboc to command
> >> line causes panic"), kgdbts_option_setup does not check input
> >> argument before passing it to strlen.  The argument would be a NULL
> >> pointer.
> >
> > Something seems to be missing here.
> >
> > The ekgdbts parameter mentioned in the subject line doesn't exist so
> > how can including it on the kernel command line could provoke a
> > panic.
> >
> > Please can you share the kernel boot arguments you used when you
> > tested this patch?
>
> I use static analysis tool to find these funcs are similar to the
> commit<1bd54d851f50>(kgdboc: Passing ekgdboc to command line causes
> panic), so it's just defensive, I haven't actually hitted this but
> there actually seems a problem here.

I don't see how a problem that occured when ekgdboc is parsed can occur
because this module does not parse ekgdbts! Are there really any
circumstances where kgdbts_option_setup() can be called with a NULL
argument?


Daniel.