From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: 4.3 serial driver crashes with console shortly after boot Date: Wed, 11 Nov 2015 17:50:36 +0100 Message-ID: <20151111165035.GL3533@two.firstfloor.org> References: <20151110002939.GG3533@two.firstfloor.org> <56414DE9.20707@hurleysoftware.com> <20151110223957.GI3533@two.firstfloor.org> <20151110224340.GA30452@two.firstfloor.org> <56427AAC.3000409@hurleysoftware.com> <56432316.3040602@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <56432316.3040602@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Hurley Cc: Andi Kleen , gregkh@linuxfoundation.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-serial@vger.kernel.org On Wed, Nov 11, 2015 at 06:14:30AM -0500, Peter Hurley wrote: > On 11/10/2015 06:15 PM, Peter Hurley wrote: > > On 11/10/2015 05:43 PM, Andi Kleen wrote: > >> On Tue, Nov 10, 2015 at 11:39:57PM +0100, Andi Kleen wrote: > >>>> I've just tried to reproduce this without success on my current > >>>> tree which has some additional patches I just posted this am. They weren't > >>>> intended to fix crashes but they directly impact the area of concern. Could > >>>> you try these three? > >>>> > >>>> [PATCH v2 2/4] n_tty: Ignore all read data when closing > >>>> [PATCH v2 3/4] tty: Abstract and encapsulate tty->closing behavior > >>>> [PATCH v2 4/4] tty: Remove drivers' extra tty_ldisc_flush() > >>>> > >>> Applying the three patches fixes the crash. > >>> I haven't tried to figure out which one did the trick. > >> > >> Actually I was wrong sorry. It still crashes, but now it doesn't > >> hang the system anymore. > > > > Argghh. > > Can you run the patch below and send me full dmesg (privately if you prefer)? > > Nevermind. I see how it's happening now; it's being initiated by hangup, > not close. FWIW, it's been like that nearly forever; your user-space/tool is > triggering this because ECHO is on. It's just agetty i believe, but there may be some funkiness going on with the terminal server or the cable. Thanks. I'll just add a NULL pointer check for now, until you have a real patch. -Andi -- ak@linux.intel.com -- Speaking for myself only.