lkml.org 
[lkml]   [2016]   [Aug]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
On Wed, Aug 03, 2016 at 08:07:02AM -0700, Guenter Roeck wrote:
> On 08/03/2016 01:38 AM, Russell King - ARM Linux wrote:
> >On Tue, Aug 02, 2016 at 07:51:45PM -0700, Guenter Roeck wrote:
> >>Hi,
> >>
> >>I see the following crash when running a qemu arm 'kzm' runtime test with
> >>the current mainline.
> >>...
> >>Failed to create /dev/root: -14
> >>
> >>[ followed by panic ]
> >>
> >>A complete log file is at [1].
> >
> >I think it's because of those undefined instructions you're hitting
> >with the hw-breakpoint code... can you try the patch below please?
> >
> > arch/arm/kernel/entry-armv.S | 1 +
> > 1 file changed, 1 insertion(+)
> >
> >diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
> >index bc5f50799d75..9f157e7c51e7 100644
> >--- a/arch/arm/kernel/entry-armv.S
> >+++ b/arch/arm/kernel/entry-armv.S
> >@@ -295,6 +295,7 @@ __und_svc_fault:
> > bl __und_fault
> >
> > __und_svc_finish:
> >+ get_thread_info tsk
> > ldr r5, [sp, #S_PSR] @ Get SVC cpsr
> > svc_exit r5 @ return from exception
> > UNWIND(.fnend )
> >
>
> Yes, that fixes the problem.
>
> Assuming you'll create a patch:
>
> Tested-by: Guenter Roeck <linux@roeck-us.net>
>
> Does that need to be addressed in qemu, or is it a Linux bug ?

It's a Linux bug provoked by qemu not implementing the hardware
breakpoints. Well worth fixing in Linux.

--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.

\
 
 \ /
  Last update: 2016-08-04 13:01    [W:0.135 / U:0.556 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site