Re: [PATCH v2] mm/hugetlb: Don't put_page in lock of hugetlb_lock

[Zhiqiang Liu]

> On 5/6/19 7:06 AM, Zhiqiang Liu wrote:
>> From: Kai Shen <shenkai8@xxxxxxxxxx>
>>
>> spinlock recursion happened when do LTP test:
>> #!/bin/bash
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>> ./runltp -p -f hugetlb &
>>
>> The dtor returned by get_compound_page_dtor in __put_compound_page
>> may be the function of free_huge_page which will lock the hugetlb_lock,
>> so don't put_page in lock of hugetlb_lock.
>>
>>  BUG: spinlock recursion on CPU#0, hugemmap05/1079
>>   lock: hugetlb_lock+0x0/0x18, .magic: dead4ead, .owner: hugemmap05/1079, .owner_cpu: 0
>>  Call trace:
>>   dump_backtrace+0x0/0x198
>>   show_stack+0x24/0x30
>>   dump_stack+0xa4/0xcc
>>   spin_dump+0x84/0xa8
>>   do_raw_spin_lock+0xd0/0x108
>>   _raw_spin_lock+0x20/0x30
>>   free_huge_page+0x9c/0x260
>>   __put_compound_page+0x44/0x50
>>   __put_page+0x2c/0x60
>>   alloc_surplus_huge_page.constprop.19+0xf0/0x140
>>   hugetlb_acct_memory+0x104/0x378
>>   hugetlb_reserve_pages+0xe0/0x250
>>   hugetlbfs_file_mmap+0xc0/0x140
>>   mmap_region+0x3e8/0x5b0
>>   do_mmap+0x280/0x460
>>   vm_mmap_pgoff+0xf4/0x128
>>   ksys_mmap_pgoff+0xb4/0x258
>>   __arm64_sys_mmap+0x34/0x48
>>   el0_svc_common+0x78/0x130
>>   el0_svc_handler+0x38/0x78
>>   el0_svc+0x8/0xc
>>
>> Fixes: 9980d744a0 ("mm, hugetlb: get rid of surplus page accounting tricks")
>> Signed-off-by: Kai Shen <shenkai8@xxxxxxxxxx>
>> Signed-off-by: Feilong Lin <linfeilong@xxxxxxxxxx>
>> Reported-by: Wang Wang <wangwang2@xxxxxxxxxx>
>> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> 
> Good catch.  Sorry, for the late reply.
> 
> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> 

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