linux-kernel - Re: [PATCH 4/7] hvc_console: Fix race between hvc_close and hvc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20100326215416.80d09610.sfr@canb.auug.org.au>
Date:	Fri, 26 Mar 2010 21:54:16 +1100
From:	Stephen Rothwell <sfr@...b.auug.org.au>
To:	Amit Shah <amit.shah@...hat.com>
Cc:	Sachin Sant <sachinp@...ibm.com>,
	Greg Kroah-Hartman <gregkh@...e.de>, a.p.zijlstra@...llo.nl,
	Rusty Russell <rusty@...tcorp.com.au>,
	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org,
	Anton Blanchard <anton@...ba.org>, tglx@...utronix.de,
	Linus Torvalds <torvalds@...ux-foundation.org>, mingo@...e.hu,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [PATCH 4/7] hvc_console: Fix race between hvc_close and
 hvc_remove

Hi Amit,

On Fri, 26 Mar 2010 15:28:21 +0530 Amit Shah <amit.shah@...hat.com> wrote:
>
> On (Fri) Mar 26 2010 [14:43:56], Sachin Sant wrote:
> >
> > I too ran into this issue as reported by Anton. Unfortunately in my
> > case the following suggested patch does not help boot the powerpc
> > box successfully. The boot still hangs with following messages

I have been getting this on my linux-next boot tests for a while as well.

> Was the hang you saw before applying this patch at the same place / for
> the same reason?

I get the same hangs with and without the patch.  Paulus bisected it
(again) to the commit below and reverting that commit fixes the problem.

> OK, this gets even murkier. I don't know why taking a few krefs modifies
> hvc_console behaviour to such an extent.
> 
> > Just to confirm i too am facing same issue as reported by Anton,
> > reverted commit e74d098c66543d0731de62eb747ccd5b636a6f4c and that allowed
> > by box to boot successfully.
> 
> Which module uses hvc_console in your case?

I assume hcv_vio.

I also tested using "init=/bin/bash" as a kernel command line option and
the console worked while I was running bash, but everything was very
sluggish.  Then when I did "exec /sbin/init" the console hung completely
- sysrq (^O) didn't even work any more (it did while I was running bash).

-- 
Cheers,
Stephen Rothwell                    sfr@...b.auug.org.au
http://www.canb.auug.org.au/~sfr/

Content of type "application/pgp-signature" skipped