* [QUESTION] arm64: mmap to the hugetlbfs with hugepagesize=512M got SIGILL
@ 2021-06-01 9:34 Yongqiang Liu
2021-06-01 15:00 ` David Hildenbrand
0 siblings, 1 reply; 3+ messages in thread
From: Yongqiang Liu @ 2021-06-01 9:34 UTC (permalink / raw)
To: catalin.marinas, will.deacon
Cc: linux-arm-kernel, linux-mm, liuyongqiang13, wangkefeng.wang
Hi Catalin and Will,
when we mmap the addr NULL with MAP_FIXED flag to the hugetlbfs, system
will return NULL successfully.
My question is: Why mmap to file with the hugepagesize=512M we got
SIGILL but mmap to the file with hugepagesize=2M we got a success ? Here
is my test steps:
1. echo 10 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
echo 10 > /sys/kernel/mm/hugepages/hugepages-524288kB/nr_hugepages
2. mount none /mnt -t tmpfs
3. mkdir /mnt/huge1
mkdir /mnt/huge2
4. mount none /mnt/huge1 -t hugetlbfs -o pagesize=512MB
mount none /mnt/huge2 -t hugetlbfs -o pagesize=2MB
5. test_case.c
... ...
fd = open("/mnt/huge1/file", O_RDWR | O_CREAT, 0777);
addr = mmap(NULL, hugepagesize, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE | MAP_FIXED, fd, 0);
... ...
The result is , mmap to the /mnt/huge1/file will got a success while
mmap to the /mnt/huge2/file will got SIGILL. Meanwile, we have found
that the kernel return the address NULL success but set the variable failed.
Here is the pc when SIGILL occured:
4009bc: 97ffff7d bl 4007b0 <mmap@plt>
pc->4009c0: aa0003e1 mov x1, x0
Kind regards,
Yongqiang Liu
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [QUESTION] arm64: mmap to the hugetlbfs with hugepagesize=512M got SIGILL
2021-06-01 9:34 [QUESTION] arm64: mmap to the hugetlbfs with hugepagesize=512M got SIGILL Yongqiang Liu
@ 2021-06-01 15:00 ` David Hildenbrand
2021-06-02 1:33 ` Yongqiang Liu
0 siblings, 1 reply; 3+ messages in thread
From: David Hildenbrand @ 2021-06-01 15:00 UTC (permalink / raw)
To: Yongqiang Liu, catalin.marinas, will.deacon
Cc: linux-arm-kernel, linux-mm, wangkefeng.wang
On 01.06.21 11:34, Yongqiang Liu wrote:
> Hi Catalin and Will,
>
> when we mmap the addr NULL with MAP_FIXED flag to the hugetlbfs, system
> will return NULL successfully.
>
> My question is: Why mmap to file with the hugepagesize=512M we got
> SIGILL but mmap to the file with hugepagesize=2M we got a success ? Here
> is my test steps:
>
> 1. echo 10 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
>
> echo 10 > /sys/kernel/mm/hugepages/hugepages-524288kB/nr_hugepages
Which values do you get when you read back these knobs?
--
Thanks,
David / dhildenb
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [QUESTION] arm64: mmap to the hugetlbfs with hugepagesize=512M got SIGILL
2021-06-01 15:00 ` David Hildenbrand
@ 2021-06-02 1:33 ` Yongqiang Liu
0 siblings, 0 replies; 3+ messages in thread
From: Yongqiang Liu @ 2021-06-02 1:33 UTC (permalink / raw)
To: David Hildenbrand, catalin.marinas, will.deacon
Cc: linux-arm-kernel, linux-mm, wangkefeng.wang
在 2021/6/1 23:00, David Hildenbrand 写道:
> On 01.06.21 11:34, Yongqiang Liu wrote:
>> Hi Catalin and Will,
>>
>> when we mmap the addr NULL with MAP_FIXED flag to the hugetlbfs, system
>> will return NULL successfully.
>>
>> My question is: Why mmap to file with the hugepagesize=512M we got
>> SIGILL but mmap to the file with hugepagesize=2M we got a success ? Here
>> is my test steps:
>>
>> 1. echo 10 >
>> /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
>>
>> echo 10 >
>> /sys/kernel/mm/hugepages/hugepages-524288kB/nr_hugepages
>
> Which values do you get when you read back these knobs?
>
> 10. I forgot that the selinux should be disabled or mmap return failed
> with error code 13.
Thanks,
Yongqiang Liu
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-06-01 9:34 [QUESTION] arm64: mmap to the hugetlbfs with hugepagesize=512M got SIGILL Yongqiang Liu
2021-06-01 15:00 ` David Hildenbrand
2021-06-02 1:33 ` Yongqiang Liu
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