On Mon, 27 Jul 2015, Borislav Petkov wrote:

> From: Borislav Petkov <bp@suse.de>
> Date: Mon, 27 Jul 2015 08:36:27 +0200
> Subject: [PATCH] cpu/cacheinfo: Fix teardown path
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> Philip Müller reported a hang when booting 32-bit 4.1 kernel on an AMD
> box. A fragment of the splat was enough to pinpoint the issue:
> 
>   task: f58e0000 ti: f58e8000 task.ti: f58e800
>   EIP: 0060:[<c135a903>] EFLAGS: 00010206 CPU: 0
>   EIP is at free_cache_attributes+0x83/0xd0
>   EAX: 00000001 EBX: f589d46c ECX: 00000090 EDX: 360c2000
>   ESI: 00000000 EDI: c1724a80 EBP: f58e9ec0 ESP: f58e9ea0
>    DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
>   CR0: 8005003b CR2: 000000ac CR3: 01731000 CR4: 000006d0
> 
> cache_shared_cpu_map_setup() did check sibling CPUs cacheinfo descriptor
> while the respective teardown path cache_shared_cpu_map_remove() didn't.
> Fix that.
> 
> >From tglx's version: to be on the safe side, move the cacheinfo
> descriptor check to free_cache_attributes(), thus cleaning up the
> hotplug path a little and making this even more robust.
> 
> Reported-by: Philip Müller <philm@manjaro.org>
> Cc: <stable@vger.kernel.org> # 4.1
> Cc: Andre Przywara <andre.przywara@arm.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: manjaro-dev@manjaro.org
> Cc: Philip Müller <philm@manjaro.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Link: https://lkml.kernel.org/r/55B47BB8.6080202@manjaro.org
> Signed-off-by: Borislav Petkov <bp@suse.de>
> ---
> 
> Moin Thomas,
> 
> I've merged both patches and tagged it for stable. Which means,
> tip-urgent.

Reviewed-by: Thomas Gleixner <tglx@linutronix.de>