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SubjectRe: [PATCH] x86/numa: kernel stack corruption fix
On 2015/4/1 16:21, Xishi Qiu wrote:

> On 2015/4/1 15:41, Dave Young wrote:
>
>> On 04/01/15 at 03:27pm, Xishi Qiu wrote:
>>> On 2015/4/1 13:11, Dave Young wrote:
>>>
>>>> Ccing Xishi Qiu who wrote the clear_kernel_node_hotplug code.
>>>>
>>>> On 04/01/15 at 12:53pm, Dave Young wrote:
>>>>> I got below kernel panic during kdump test on Thinkpad T420 laptop:
>>>>>
>>>>> [ 0.000000] No NUMA configuration found
>>>>> [ 0.000000] Faking a node at [mem 0x0000000000000000-0x0000000037ba4fff]
>>>>> [ 0.000000] Kernel panic - not syncing: stack-protector: Kernel stack is cor
>>>>> upted in: ffffffff81d21910 r
>>>>> [ 0.000000]
>>>>> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44
>>>>> [ 0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/
>>>>> 5/2013 0
>>>>> [ 0.000000] 0000000000000000 c70296ddd809e4f6 ffffffff81b67ce8 ffffffff817c
>>>>> a26 2
>>>>> [ 0.000000] 0000000000000000 ffffffff81a61c90 ffffffff81b67d68 ffffffff817b
>>>>> 8d2 c
>>>>> [ 0.000000] 0000000000000010 ffffffff81b67d78 ffffffff81b67d18 c70296ddd809
>>>>> 4f6 e
>>>>> [ 0.000000] Call Trace:
>>>>> [ 0.000000] [<ffffffff817c2a26>] dump_stack+0x45/0x57
>>>>> [ 0.000000] [<ffffffff817bc8d2>] panic+0xd0/0x204
>>>>> [ 0.000000] [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2
>>>>> [ 0.000000] [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20
>>>>> [ 0.000000] [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2
>>>>> [ 0.000000] [<ffffffff81d21e5d>] numa_init+0x1a5/0x520
>>>>> [ 0.000000] [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d
>>>>> [ 0.000000] [<ffffffff81d22460>] initmem_init+0x9/0xb
>>>>> [ 0.000000] [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff817bd0bb>] ? printk+0x55/0x6b
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c
>>>>> [ 0.000000] [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184
>>>>> [ 0.000000] ---[ end Kernel panic - not syncing: stack-protector: Kernel sta
>>>>> k is corrupted in: ffffffff81d21910 c
>>>>> [ 0.000000]
>>>>> PANIC: early exception 0d rip 10:ffffffff8105d2a6 error 7eb cr2 ffff8800371dd00
>>>>> [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.0.0-rc6+ #44 0
>>>>> [ 0.000000] Hardware name: LENOVO 4236NUC/4236NUC, BIOS 83ET76WW (1.46 ) 07/
>>>>> 5/2013 0
>>>>> [ 0.000000] 0000000000000000 c70296ddd809e4f6 ffffffff81b67c60 ffffffff817c
>>>>> a26 2
>>>>> [ 0.000000] 0000000000000096 ffffffff81a61c90 ffffffff81b67d68 fffffff00000
>>>>> 084 0000000000000a0d 0000000000000a00 0
>>>>> [ 0.000000] Call Trace:
>>>>> [ 0.000000] [<ffffffff817c2a26>] dump_stack+0x45/0x57
>>>>> [ 0.000000] [<ffffffff81d051b0>] early_idt_handler+0x90/0xb7
>>>>> [ 0.000000] [<ffffffff8105d2a6>] ? native_irq_enable+0x6/0x10
>>>>> [ 0.000000] [<ffffffff817bc9c5>] ? panic+0x1c3/0x204
>>>>> [ 0.000000] [<ffffffff81d21910>] ? numa_clear_kernel_node_hotplug+0xe6/0xf2
>>>>> [ 0.000000] [<ffffffff8107741b>] __stack_chk_fail+0x1b/0x20
>>>>> [ 0.000000] [<ffffffff81d21910>] numa_clear_kernel_node_hotplug+0xe6/0xf2
>>>>> [ 0.000000] [<ffffffff81d21e5d>] numa_init+0x1a5/0x520
>>>>> [ 0.000000] [<ffffffff81d222b1>] x86_numa_init+0x19/0x3d
>>>>> [ 0.000000] [<ffffffff81d22460>] initmem_init+0x9/0xb
>>>>> [ 0.000000] [<ffffffff81d0d00c>] setup_arch+0x94f/0xc82
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff817bd0bb>] ? printk+0x55/0x6b
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d05d9b>] start_kernel+0xe8/0x4d6
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d05120>] ? early_idt_handlers+0x120/0x120
>>>>> [ 0.000000] [<ffffffff81d055ee>] x86_64_start_reservations+0x2a/0x2c
>>>>> [ 0.000000] [<ffffffff81d05751>] x86_64_start_kernel+0x161/0x184
>>>>> [ 0.000000] RIP 0x46
>>>>>
>>>>> This is caused by writing over end of numa mask bitmap.
>>>>>
>>>>> numa_clear_kernel_node try to set node id in a mask bitmap, it iterating all
>>>>> reserved region and assume every regions have valid nid. It is not true because
>>>>> There's an exception for graphic memory quirks. see function trim_snb_memory
>>>>> in arch/x86/kernel/setup.c
>>>>>
>>>>> It is easily to reproduce the bug in kdump kernel because kdump kernel use
>>>>> prereserved memory instead of whole memory, but kexec pass other reserved memory
>>>>> ranges to 2nd kernel as well. like below in my test:
>>>>> kdump kernel ram 0x2d000000 - 0x37bfffff
>>>>> One of the reserved regions: 0x40000000 - 0x40100000
>>>>>
>>>>> The above reserved region includes 0x40004000, a page excluded in
>>>>> trim_snb_memory. For this memblock reserved region the nid is not set it is
>>>>> still default value MAX_NUMNODES. later node_set callback will set bit
>>>>> MAX_NUMNODES in nodemask bitmap thus stack corruption happen.
>>>>>
>>>
>>> Hi Dave,
>>>
>>> Is it means, first reserved region 0x40000000 - 0x40100000, then boot the kdump
>>> kernel, so this region is not include in "numa_meminfo", and memblock.reserved
>>> (0x40004000) is still MAX_NUMNODES from trim_snb_memory().
>>
>> Right, btw, I booted kdump kernel with numa=off for saving memory.
>>
>> I suspect it will also be reproduced with mem=XYZ with normal kernel.
>>
>
> cc Tang Chen, numa_clear_kernel_node_hotplug() is original written by him.
>
> Hi Dave,
> I tested the problem, and find the kdump's "numa_meminfo" is the same as the first
> kernel. I did not set "numa=off" in kdump kernel, maybe this will lead to the
> difference of "numa_meminfo"
>

Hi Dave,

I find the reason, it's "dummy_numa_init() -> numa_add_memblk(0, 0, PFN_PHYS(max_pfn));",
this lead to the difference of "numa_meminfo" when set "numa=off".

However we should fix the bug when set "numa=off".


Thanks,
Xishi Qiu




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