Messages in this thread | | | From | Gregory CLEMENT <> | Subject | Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception") | Date | Tue, 09 Aug 2016 17:06:51 +0200 |
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Hi Russell King,
On jeu., août 04 2016, Russell King - ARM Linux <linux@armlinux.org.uk> wrote:
> 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.
The Armada XP base platform were hit by the same bug as we can see on kernlci: https://storage.kernelci.org/mainline/v4.8-rc1/arm-mvebu_v7_defconfig/lab-baylibre-seattle/boot-armada-xp-openblocks-ax3-4.html
Your patch solves the issue too.
Will you push this patch for v4.8-rc2 ?
Also I wonder if it is something expected to have this issue on a "real" hardware.
You can also add my: Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Thanks,
Gregory
> > -- > 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. > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
-- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com
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