2021-06-28 05:51:42

by Lianjie Zhang

Subject: [PATCH v2] mm: Fix the problem of mips architecture Oops

The cause of the problem is as follows:
1. when cat /sys/devices/system/memory/memory0/valid_zones,
test_pages_in_a_zone() will be called.
2. test_pages_in_a_zone() finds the zone according to stat_pfn = 0.
The smallest pfn of the numa node in the mips architecture is 128,
and the page corresponding to the previous 0~127 pfn is not
initialized (page->flags is 0xFFFFFFFF)
3. The nid and zonenum obtained using page_zone(pfn_to_page(0)) are out
of bounds in the corresponding array,
&NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)],
access to the out-of-bounds zone member variables appear abnormal,
resulting in Oops.
Therefore, it is necessary to keep the page between 0 and the minimum
pfn to prevent Oops from appearing.

Signed-off-by: zhanglianjie <[email protected]>
---
arch/mips/loongson64/numa.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
index fa9b4a487a47..dba9e6f17b9e 100644
--- a/arch/mips/loongson64/numa.c
+++ b/arch/mips/loongson64/numa.c
@@ -129,6 +129,9 @@ static void __init node_mem_init(unsigned int node)
if (node_end_pfn(0) >= (0xffffffff >> PAGE_SHIFT))
memblock_reserve((node_addrspace_offset | 0xfe000000),
32 << 20);
+
+ /* Reserver pfn range 0~node[0]->node_start_pfn */
+ memblock_reserve(0, PAGE_SIZE * start_pfn);
}
}

--
2.20.1

2021-06-28 08:52:45

by Sergei Shtylyov

Subject: Re: [PATCH v2] mm: Fix the problem of mips architecture Oops

Hello!

On 28.06.2021 8:47, zhanglianjie wrote:

> The cause of the problem is as follows:
> 1. when cat /sys/devices/system/memory/memory0/valid_zones,
> test_pages_in_a_zone() will be called.
> 2. test_pages_in_a_zone() finds the zone according to stat_pfn = 0.
> The smallest pfn of the numa node in the mips architecture is 128,
> and the page corresponding to the previous 0~127 pfn is not
> initialized (page->flags is 0xFFFFFFFF)
> 3. The nid and zonenum obtained using page_zone(pfn_to_page(0)) are out
> of bounds in the corresponding array,
> &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)],
> access to the out-of-bounds zone member variables appear abnormal,
> resulting in Oops.
> Therefore, it is necessary to keep the page between 0 and the minimum
> pfn to prevent Oops from appearing.
>
> Signed-off-by: zhanglianjie <[email protected]>
> ---
> arch/mips/loongson64/numa.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
> index fa9b4a487a47..dba9e6f17b9e 100644
> --- a/arch/mips/loongson64/numa.c
> +++ b/arch/mips/loongson64/numa.c
> @@ -129,6 +129,9 @@ static void __init node_mem_init(unsigned int node)
> if (node_end_pfn(0) >= (0xffffffff >> PAGE_SHIFT))
> memblock_reserve((node_addrspace_offset | 0xfe000000),
> 32 << 20);
> +
> + /* Reserver pfn range 0~node[0]->node_start_pfn */

Reserve?

> + memblock_reserve(0, PAGE_SIZE * start_pfn);
> }
> }
[...]

MBR, Sergei

2021-06-28 09:07:13

by Lianjie Zhang

Subject: Re: [PATCH v2] mm: Fix the problem of mips architecture Oops

On 2021-06-28 16:51, Sergei Shtylyov wrote:
> Hello!
>
> On 28.06.2021 8:47, zhanglianjie wrote:
>
>> The cause of the problem is as follows:
>> 1. when cat /sys/devices/system/memory/memory0/valid_zones,
>>     test_pages_in_a_zone() will be called.
>> 2. test_pages_in_a_zone() finds the zone according to stat_pfn = 0.
>>     The smallest pfn of the numa node in the mips architecture is 128,
>>     and the page corresponding to the previous 0~127 pfn is not
>>     initialized (page->flags is 0xFFFFFFFF)
>> 3. The nid and zonenum obtained using page_zone(pfn_to_page(0)) are out
>>     of bounds in the corresponding array,
>>     &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)],
>>     access to the out-of-bounds zone member variables appear abnormal,
>>     resulting in Oops.
>> Therefore, it is necessary to keep the page between 0 and the minimum
>> pfn to prevent Oops from appearing.
>>
>> Signed-off-by: zhanglianjie <[email protected]>
>> ---
>>   arch/mips/loongson64/numa.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/arch/mips/loongson64/numa.c b/arch/mips/loongson64/numa.c
>> index fa9b4a487a47..dba9e6f17b9e 100644
>> --- a/arch/mips/loongson64/numa.c
>> +++ b/arch/mips/loongson64/numa.c
>> @@ -129,6 +129,9 @@ static void __init node_mem_init(unsigned int node)
>>           if (node_end_pfn(0) >= (0xffffffff >> PAGE_SHIFT))
>>               memblock_reserve((node_addrspace_offset | 0xfe000000),
>>                        32 << 20);
>> +
>> +        /* Reserver pfn range 0~node[0]->node_start_pfn */
>
>    Reserve?
>
>> +        memblock_reserve(0, PAGE_SIZE * start_pfn);
>>       }
>>   }
> [...]
>
> MBR, Sergei
>
>

Oh, I’m so sorry. I will resubmit, thanks for your reminder.

--
Regards,
Zhang Lianjie