* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-03 2:51 ` Guenter Roeck
0 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-03 2:51 UTC (permalink / raw)
To: Russell King; +Cc: linux-kernel, linux-arm-kernel, Will Deacon
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].
Bisect points to commit e6978e4bf1 ("ARM: save and reset the address limit when entering
an exception"). Some additional debugging shows lots of similar error returns from
strncpy_from_user(). For the error case resulting in the crash, the call chain
is as follows.
sys_mknod
sys_mknodat()
user_path_create()
getname()
getname_flags()
strncpy_from_user()
Reverting the patch fixes the problem.
I don't see the problem with any other qemu arm test.
It looks like the kernel runs in exception context. My gut feeling is that qemu may be
to blame, but I am not really sure.
Any idea how to track this down ?
Thanks,
Guenter
---
[1] http://kerneltests.org/builders/qemu-arm-master/builds/615
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-03 2:51 ` Guenter Roeck
0 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-03 2:51 UTC (permalink / raw)
To: linux-arm-kernel
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].
Bisect points to commit e6978e4bf1 ("ARM: save and reset the address limit when entering
an exception"). Some additional debugging shows lots of similar error returns from
strncpy_from_user(). For the error case resulting in the crash, the call chain
is as follows.
sys_mknod
sys_mknodat()
user_path_create()
getname()
getname_flags()
strncpy_from_user()
Reverting the patch fixes the problem.
I don't see the problem with any other qemu arm test.
It looks like the kernel runs in exception context. My gut feeling is that qemu may be
to blame, but I am not really sure.
Any idea how to track this down ?
Thanks,
Guenter
---
[1] http://kerneltests.org/builders/qemu-arm-master/builds/615
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-03 2:51 ` Guenter Roeck
@ 2016-08-03 8:38 ` Russell King - ARM Linux
-1 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-03 8:38 UTC (permalink / raw)
To: Guenter Roeck; +Cc: linux-kernel, linux-arm-kernel, Will Deacon
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 )
--
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.
^ permalink raw reply related [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-03 8:38 ` Russell King - ARM Linux
0 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-03 8:38 UTC (permalink / raw)
To: linux-arm-kernel
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 )
--
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.
^ permalink raw reply related [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-03 8:38 ` Russell King - ARM Linux
@ 2016-08-03 15:07 ` Guenter Roeck
-1 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-03 15:07 UTC (permalink / raw)
To: Russell King - ARM Linux; +Cc: linux-kernel, linux-arm-kernel, Will Deacon
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 ?
Thanks,
Guenter
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-03 15:07 ` Guenter Roeck
0 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-03 15:07 UTC (permalink / raw)
To: linux-arm-kernel
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 ?
Thanks,
Guenter
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-03 15:07 ` Guenter Roeck
@ 2016-08-04 10:07 ` Russell King - ARM Linux
-1 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-04 10:07 UTC (permalink / raw)
To: Guenter Roeck; +Cc: linux-kernel, linux-arm-kernel, Will Deacon
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.
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-04 10:07 ` Russell King - ARM Linux
0 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-04 10:07 UTC (permalink / raw)
To: linux-arm-kernel
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.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-04 10:07 ` Russell King - ARM Linux
@ 2016-08-09 15:06 ` Gregory CLEMENT
-1 siblings, 0 replies; 18+ messages in thread
From: Gregory CLEMENT @ 2016-08-09 15:06 UTC (permalink / raw)
To: Russell King - ARM Linux
Cc: Guenter Roeck, Will Deacon, linux-kernel, linux-arm-kernel
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
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-09 15:06 ` Gregory CLEMENT
0 siblings, 0 replies; 18+ messages in thread
From: Gregory CLEMENT @ 2016-08-09 15:06 UTC (permalink / raw)
To: linux-arm-kernel
Hi Russell King,
On jeu., ao?t 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 at 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
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-09 15:06 ` Gregory CLEMENT
@ 2016-08-09 16:12 ` Guenter Roeck
-1 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-09 16:12 UTC (permalink / raw)
To: Gregory CLEMENT
Cc: Russell King - ARM Linux, Will Deacon, linux-kernel, linux-arm-kernel
On Tue, Aug 09, 2016 at 05:06:51PM +0200, Gregory CLEMENT wrote:
> 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.
>
It would be expected if hardware breakpoint implementation is optional
and not all real CPUs implement it.
Guenter
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-09 16:12 ` Guenter Roeck
0 siblings, 0 replies; 18+ messages in thread
From: Guenter Roeck @ 2016-08-09 16:12 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, Aug 09, 2016 at 05:06:51PM +0200, Gregory CLEMENT wrote:
> Hi Russell King,
>
> On jeu., ao?t 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.
>
It would be expected if hardware breakpoint implementation is optional
and not all real CPUs implement it.
Guenter
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-09 15:06 ` Gregory CLEMENT
@ 2016-08-10 23:34 ` Kevin Hilman
-1 siblings, 0 replies; 18+ messages in thread
From: Kevin Hilman @ 2016-08-10 23:34 UTC (permalink / raw)
To: Gregory CLEMENT
Cc: Russell King - ARM Linux, Guenter Roeck, Will Deacon,
linux-kernel, linux-arm-kernel
On Tue, Aug 9, 2016 at 10:06 AM, Gregory CLEMENT
<gregory.clement@free-electrons.com> wrote:
> 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>
I also tested this fixes the boot issue on Armada XP.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Kevin
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-10 23:34 ` Kevin Hilman
0 siblings, 0 replies; 18+ messages in thread
From: Kevin Hilman @ 2016-08-10 23:34 UTC (permalink / raw)
To: linux-arm-kernel
On Tue, Aug 9, 2016 at 10:06 AM, Gregory CLEMENT
<gregory.clement@free-electrons.com> wrote:
> Hi Russell King,
>
> On jeu., ao?t 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>
I also tested this fixes the boot issue on Armada XP.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Kevin
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-10 23:34 ` Kevin Hilman
@ 2016-08-10 23:43 ` Russell King - ARM Linux
-1 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-10 23:43 UTC (permalink / raw)
To: Kevin Hilman
Cc: Gregory CLEMENT, Guenter Roeck, Will Deacon, linux-kernel,
linux-arm-kernel
On Wed, Aug 10, 2016 at 06:34:22PM -0500, Kevin Hilman wrote:
> I also tested this fixes the boot issue on Armada XP.
>
> Tested-by: Kevin Hilman <khilman@baylibre.com>
It should be in the current linux-next. I'll send them on in the
usual way over the weekend for -rc2, with your ack for this one.
Thanks.
--
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.
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-10 23:43 ` Russell King - ARM Linux
0 siblings, 0 replies; 18+ messages in thread
From: Russell King - ARM Linux @ 2016-08-10 23:43 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Aug 10, 2016 at 06:34:22PM -0500, Kevin Hilman wrote:
> I also tested this fixes the boot issue on Armada XP.
>
> Tested-by: Kevin Hilman <khilman@baylibre.com>
It should be in the current linux-next. I'll send them on in the
usual way over the weekend for -rc2, with your ack for this one.
Thanks.
--
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.
^ permalink raw reply [flat|nested] 18+ messages in thread
* Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
2016-08-10 23:43 ` Russell King - ARM Linux
@ 2016-08-11 0:46 ` Kevin Hilman
-1 siblings, 0 replies; 18+ messages in thread
From: Kevin Hilman @ 2016-08-11 0:46 UTC (permalink / raw)
To: Russell King - ARM Linux
Cc: Gregory CLEMENT, Guenter Roeck, Will Deacon, linux-kernel,
linux-arm-kernel
On Wed, Aug 10, 2016 at 6:43 PM, Russell King - ARM Linux
<linux@armlinux.org.uk> wrote:
> On Wed, Aug 10, 2016 at 06:34:22PM -0500, Kevin Hilman wrote:
>> I also tested this fixes the boot issue on Armada XP.
>>
>> Tested-by: Kevin Hilman <khilman@baylibre.com>
>
> It should be in the current linux-next. I'll send them on in the
> usual way over the weekend for -rc2, with your ack for this one.
Also, I noticed your for-next branch is going through boot testing
right now in my kernelci lab, and I see it passed on the Armada XP, so
that's more evidence for the fix.
Thanks,
Kevin
^ permalink raw reply [flat|nested] 18+ messages in thread
* "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception")
@ 2016-08-11 0:46 ` Kevin Hilman
0 siblings, 0 replies; 18+ messages in thread
From: Kevin Hilman @ 2016-08-11 0:46 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Aug 10, 2016 at 6:43 PM, Russell King - ARM Linux
<linux@armlinux.org.uk> wrote:
> On Wed, Aug 10, 2016 at 06:34:22PM -0500, Kevin Hilman wrote:
>> I also tested this fixes the boot issue on Armada XP.
>>
>> Tested-by: Kevin Hilman <khilman@baylibre.com>
>
> It should be in the current linux-next. I'll send them on in the
> usual way over the weekend for -rc2, with your ack for this one.
Also, I noticed your for-next branch is going through boot testing
right now in my kernelci lab, and I see it passed on the Armada XP, so
that's more evidence for the fix.
Thanks,
Kevin
^ permalink raw reply [flat|nested] 18+ messages in thread
end of thread, other threads:[~2016-08-11 0:46 UTC | newest]
Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-03 2:51 "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception") Guenter Roeck
2016-08-03 2:51 ` Guenter Roeck
2016-08-03 8:38 ` Russell King - ARM Linux
2016-08-03 8:38 ` Russell King - ARM Linux
2016-08-03 15:07 ` Guenter Roeck
2016-08-03 15:07 ` Guenter Roeck
2016-08-04 10:07 ` Russell King - ARM Linux
2016-08-04 10:07 ` Russell King - ARM Linux
2016-08-09 15:06 ` Gregory CLEMENT
2016-08-09 15:06 ` Gregory CLEMENT
2016-08-09 16:12 ` Guenter Roeck
2016-08-09 16:12 ` Guenter Roeck
2016-08-10 23:34 ` Kevin Hilman
2016-08-10 23:34 ` Kevin Hilman
2016-08-10 23:43 ` Russell King - ARM Linux
2016-08-10 23:43 ` Russell King - ARM Linux
2016-08-11 0:46 ` Kevin Hilman
2016-08-11 0:46 ` Kevin Hilman
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