2012-05-31 12:59:40

by Liu, Jinsong

[permalink] [raw]
Subject: [PATCH 2/2] initcall sequence adjust for 3 funcs

>From eb5ff1bef5dd3116fa2624b594b853e9334ccbce Mon Sep 17 00:00:00 2001
From: root <[email protected]>
Date: Fri, 1 Jun 2012 03:56:25 +0800
Subject: [PATCH 2/2] initcall sequence adjust for 3 funcs

there are 3 funcs need to be _initcalled in a logic sequence:
1. xen_late_init_mcelog
2. mcheck_init_device
3. threshold_init_device

xen_late_init_mcelog need register xen_mce_chrdev_device before
native mce_chrdev_device registeration if running under xen platform;

mcheck_init_device should be inited before threshold_init_device to
initialize mce_device, otherwise a NULL pointer would occur and panic.

so we use following _initcalls
1. device_initcall(xen_late_init_mcelog);
2. device_initcall_sync(mcheck_init_device);
3. late_initcall(threshold_init_device);

when running under xen platform, 1,2,3 would take effect;
when running under baremetal, 2,3 would take effect;

Reported-by: Borislav Petkov <[email protected]>
Suggested-by: Konrad Rzeszutek Wilk <[email protected]>
Signed-off-by: Liu, Jinsong <[email protected]>
---
arch/x86/kernel/cpu/mcheck/mce_amd.c | 22 +++++++++++++++++++++-
1 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index f4873a6..6647858 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -777,4 +777,24 @@ static __init int threshold_init_device(void)

return 0;
}
-device_initcall(threshold_init_device);
+/*
+ * there are 3 funcs need to be _initcalled in a logic sequence:
+ * 1. xen_late_init_mcelog
+ * 2. mcheck_init_device
+ * 3. threshold_init_device
+ *
+ * xen_late_init_mcelog need register xen_mce_chrdev_device before
+ * native mce_chrdev_device registeration if running under xen platform;
+ *
+ * mcheck_init_device should be inited before threshold_init_device to
+ * initialize mce_device, otherwise a NULL pointer would occur and panic.
+ *
+ * so we use following _initcalls
+ * 1. device_initcall(xen_late_init_mcelog);
+ * 2. device_initcall_sync(mcheck_init_device);
+ * 3. late_initcall(threshold_init_device);
+ *
+ * when running under xen platform, 1,2,3 would take effect;
+ * when running under baremetal, 2,3 would take effect;
+ */
+late_initcall(threshold_init_device);
--
1.7.1


Attachments:
0002-initcall-sequence-adjust-for-3-funcs.patch (2.25 kB)
0002-initcall-sequence-adjust-for-3-funcs.patch

2012-05-31 13:53:27

by Borislav Petkov

[permalink] [raw]
Subject: Re: [PATCH 2/2] initcall sequence adjust for 3 funcs

Just minor nitpicks below:

On Thu, May 31, 2012 at 12:59:05PM +0000, Liu, Jinsong wrote:
> From eb5ff1bef5dd3116fa2624b594b853e9334ccbce Mon Sep 17 00:00:00 2001
> From: root <[email protected]>
> Date: Fri, 1 Jun 2012 03:56:25 +0800
> Subject: [PATCH 2/2] initcall sequence adjust for 3 funcs

Change subject line to

Subject: [PATCH 2/2] x86, MCE, AMD: Adjust initcall sequence for xen

> there are 3 funcs need to be _initcalled in a logic sequence:
> 1. xen_late_init_mcelog
> 2. mcheck_init_device
> 3. threshold_init_device
>
> xen_late_init_mcelog need register xen_mce_chrdev_device before
> native mce_chrdev_device registeration if running under xen platform;
>
> mcheck_init_device should be inited before threshold_init_device to
> initialize mce_device, otherwise a NULL pointer would occur and panic.
>
> so we use following _initcalls
> 1. device_initcall(xen_late_init_mcelog);
> 2. device_initcall_sync(mcheck_init_device);
> 3. late_initcall(threshold_init_device);
>
> when running under xen platform, 1,2,3 would take effect;
> when running under baremetal, 2,3 would take effect;
>
> Reported-by: Borislav Petkov <[email protected]>
> Suggested-by: Konrad Rzeszutek Wilk <[email protected]>
> Signed-off-by: Liu, Jinsong <[email protected]>
> ---
> arch/x86/kernel/cpu/mcheck/mce_amd.c | 22 +++++++++++++++++++++-
> 1 files changed, 21 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> index f4873a6..6647858 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> @@ -777,4 +777,24 @@ static __init int threshold_init_device(void)
>
> return 0;
> }
> -device_initcall(threshold_init_device);
> +/*
> + * there are 3 funcs need to be _initcalled in a logic sequence:

which need...

> + * 1. xen_late_init_mcelog
> + * 2. mcheck_init_device
> + * 3. threshold_init_device
> + *
> + * xen_late_init_mcelog need register xen_mce_chrdev_device before

s/need/must/

> + * native mce_chrdev_device registeration if running under xen platform;

registration

> + *
> + * mcheck_init_device should be inited before threshold_init_device to
> + * initialize mce_device, otherwise a NULL pointer would occur and panic.

a NULL ptr dereference will cause panic.

> + *
> + * so we use following _initcalls
> + * 1. device_initcall(xen_late_init_mcelog);
> + * 2. device_initcall_sync(mcheck_init_device);
> + * 3. late_initcall(threshold_init_device);
> + *
> + * when running under xen platform, 1,2,3 would take effect;
> + * when running under baremetal, 2,3 would take effect;

change both lines above to say:

"when running under xen, the initcall order is 1,2,3;
on baremetal, we skip 1 and we do only 2 and 3."

The rest looks ok and it tests fine here.

Once you've changed the minor stuff above, you can slap my

Acked-and-tested-by: Borislav Petkov <[email protected]>

@Tony: if you have any objections, please scream now! :-)

Thanks Jinsong!

--
Regards/Gruss,
Boris.

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