Re: [lockdep] b09be676e0 BUG: unable to handle kernel NULL pointer dereference at 000001f2

From: Josh Poimboeuf
Date: Mon Oct 09 2017 - 09:03:35 EST


On Mon, Oct 09, 2017 at 02:54:04PM +0200, Peter Zijlstra wrote:
> On Mon, Oct 09, 2017 at 08:21:13PM +0800, Fengguang Wu wrote:
> > > > From e7840ad76515f0b5061fcdd098b57b7c01b61482 Mon Sep 17 00:00:00 2001
> > > > Message-Id: <e7840ad76515f0b5061fcdd098b57b7c01b61482.1507215196.git.jpoimboe@xxxxxxxxxx>
> > > > From: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> > > > Date: Thu, 5 Oct 2017 09:43:59 -0500
> > > > Subject: [PATCH 1/2] unwinder fixes
> > > >
> > > > ---
> > > > arch/x86/kernel/unwind_frame.c | 33 ++++++++++++++++++++++++++++++---
> >
> > I just test 316 boots and see 7 WARNINGs:
> >
> > [ 404.948035] WARNING: kernel stack frame pointer at c6ea3ecd in init:212 has bad value (null)
> > [ 298.118383] WARNING: kernel stack frame pointer at cde07dad in init:1 has bad value bc000000
> > [ 112.848677] WARNING: kernel stack frame pointer at cde07dbd in swapper/0:1 has bad value c2000000
> > [ 127.942417] WARNING: kernel stack frame pointer at cf95de71 in rb_producer:50 has bad value 03cf95de
> > [ 4.736938] WARNING: kernel stack frame pointer at bf643d59 in kworker/0:1:15 has bad value b5000000
> > [ 308.260066] WARNING: kernel stack frame pointer at bde07da5 in udevd:155 has bad value b5bfa17b

These unwinder warnings can be ignored. I meant to disable them on
32-bit with the patch, but obviously failed to do so.

--
Josh