linux-kernel - Re: arm32: panic in move_freepages (Was [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn

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Message-ID: <ca5b00bd-1312-0c69-ab69-a1bd749f51b6@huawei.com>
Date:   Fri, 30 Apr 2021 19:24:37 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Mike Rapoport <rppt@...nel.org>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        David Hildenbrand <david@...hat.com>,
        Marc Zyngier <maz@...nel.org>,
        "Mark Rutland" <mark.rutland@....com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        "Will Deacon" <will@...nel.org>, <kvmarm@...ts.cs.columbia.edu>,
        <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>
Subject: Re: arm32: panic in move_freepages (Was [PATCH v2 0/4] arm64: drop
 pfn_valid_within() and simplify pfn_valid())



On 2021/4/30 17:51, Mike Rapoport wrote:
> On Thu, Apr 29, 2021 at 06:22:55PM +0800, Kefeng Wang wrote:
>>
>> On 2021/4/29 14:57, Mike Rapoport wrote:
>>
>>>>> Do you use SPARSMEM? If yes, what is your section size?
>>>>> What is the value if CONFIG_FORCE_MAX_ZONEORDER in your configuration?
>>>> Yes,
>>>>
>>>> CONFIG_SPARSEMEM=y
>>>>
>>>> CONFIG_SPARSEMEM_STATIC=y
>>>>
>>>> CONFIG_FORCE_MAX_ZONEORDER = 11
>>>>
>>>> CONFIG_PAGE_OFFSET=0xC0000000
>>>> CONFIG_HAVE_ARCH_PFN_VALID=y
>>>> CONFIG_HIGHMEM=y
>>>> #define SECTION_SIZE_BITS    26
>>>> #define MAX_PHYSADDR_BITS    32
>>>> #define MAX_PHYSMEM_BITS     32
>>
>>
>> With the patch,  the addr is aligned, but the panic still occurred,
> 
> Is this the same panic at move_freepages() for range [de600, de7ff]?
> 
> Do you enable CONFIG_ARM_LPAE?

no, the CONFIG_ARM_LPAE is not set, and yes with same panic at 
move_freepages at

start_pfn/end_pfn [de600, de7ff], [de600000, de7ff000] :  pfn =de600, 
page =ef3cc000, page-flags = ffffffff,  pfn2phy = de600000



> 
>> new free memory log is below,
>>
>> memblock_free: [0xaf430000-0xaf44ffff] mem_init+0x158/0x23c
>>
>> memblock_free: [0xaf510000-0xaf53ffff] mem_init+0x158/0x23c
>> memblock_free: [0xaf560000-0xaf57ffff] mem_init+0x158/0x23c
>> memblock_free: [0xafd98000-0xafdc7fff] mem_init+0x158/0x23c
>> memblock_free: [0xafdd8000-0xafdfffff] mem_init+0x158/0x23c
>> memblock_free: [0xafe18000-0xafe7ffff] mem_init+0x158/0x23c
>> memblock_free: [0xafee0000-0xafefffff] mem_init+0x158/0x23c
>> __free_memory_core, range: 0x80a03000 - 0x80a04000, pfn: 80a03 - 80a04
>> __free_memory_core, range: 0x80a08000 - 0x80b00000, pfn: 80a08 - 80b00
>> __free_memory_core, range: 0x812e8058 - 0x83000000, pfn: 812e9 - 83000
>> __free_memory_core, range: 0x85000000 - 0x85600000, pfn: 85000 - 85600
>> __free_memory_core, range: 0x86a00000 - 0x87e00000, pfn: 86a00 - 87e00
>> __free_memory_core, range: 0x8bd00000 - 0x8c500000, pfn: 8bd00 - 8c500
>> __free_memory_core, range: 0x8e300000 - 0x8ed00000, pfn: 8e300 - 8ed00
>> __free_memory_core, range: 0x90d00000 - 0xaf2c0000, pfn: 90d00 - af2c0
>> __free_memory_core, range: 0xaf430000 - 0xaf450000, pfn: af430 - af450
>> __free_memory_core, range: 0xaf510000 - 0xaf540000, pfn: af510 - af540
>> __free_memory_core, range: 0xaf560000 - 0xaf580000, pfn: af560 - af580
>> __free_memory_core, range: 0xafd98000 - 0xafdc8000, pfn: afd98 - afdc8
>> __free_memory_core, range: 0xafdd8000 - 0xafe00000, pfn: afdd8 - afe00
>> __free_memory_core, range: 0xafe18000 - 0xafe80000, pfn: afe18 - afe80
>> __free_memory_core, range: 0xafee0000 - 0xaff00000, pfn: afee0 - aff00
>> __free_memory_core, range: 0xaff80000 - 0xaff8d000, pfn: aff80 - aff8d
>> __free_memory_core, range: 0xafff2000 - 0xafff4580, pfn: afff2 - afff4
>> __free_memory_core, range: 0xafffe000 - 0xafffe0e0, pfn: afffe - afffe
>> __free_memory_core, range: 0xafffe4fc - 0xafffe500, pfn: affff - afffe
>> __free_memory_core, range: 0xafffe6e4 - 0xafffe700, pfn: affff - afffe
>> __free_memory_core, range: 0xafffe8dc - 0xafffe8e0, pfn: affff - afffe
>> __free_memory_core, range: 0xafffe970 - 0xafffe980, pfn: affff - afffe
>> __free_memory_core, range: 0xafffe990 - 0xafffe9a0, pfn: affff - afffe
>> __free_memory_core, range: 0xafffe9a4 - 0xafffe9c0, pfn: affff - afffe
>> __free_memory_core, range: 0xafffeb54 - 0xafffeb60, pfn: affff - afffe
>> __free_memory_core, range: 0xafffecf4 - 0xafffed00, pfn: affff - afffe
>> __free_memory_core, range: 0xafffefc4 - 0xafffefd8, pfn: affff - afffe
>> __free_memory_core, range: 0xb0200000 - 0xc0000000, pfn: b0200 - b0200
>> __free_memory_core, range: 0xcc000000 - 0xdca00000, pfn: cc000 - b0200
>> __free_memory_core, range: 0xde700000 - 0xdea00000, pfn: de700 - b0200
> 
> The range [de600, de7ff]
the __free_memory_core will check the start pfn and end pfn,

  if (start_pfn >= end_pfn)
          return 0;

  __free_pages_memory(start_pfn, end_pfn);
so the memory will not be freed to buddy, confused...
> 
>> __free_memory_core, range: 0xe0800000 - 0xe0c00000, pfn: e0800 - b0200
>> __free_memory_core, range: 0xf4b00000 - 0xf7000000, pfn: f4b00 - b0200
>> __free_memory_core, range: 0xfda00000 - 0xffffffff, pfn: fda00 - b0200
>>> It seems that with SPARSEMEM we don't align the freed parts on pageblock
>>> boundaries.
>>>
>>> Can you try the patch below:
>>>
>>> diff --git a/mm/memblock.c b/mm/memblock.c
>>> index afaefa8fc6ab..1926369b52ec 100644
>>> --- a/mm/memblock.c
>>> +++ b/mm/memblock.c
>>> @@ -1941,14 +1941,13 @@ static void __init free_unused_memmap(void)
>>>    		 * due to SPARSEMEM sections which aren't present.
>>>    		 */
>>>    		start = min(start, ALIGN(prev_end, PAGES_PER_SECTION));
>>> -#else
>>> +#endif
>>>    		/*
>>>    		 * Align down here since the VM subsystem insists that the
>>>    		 * memmap entries are valid from the bank start aligned to
>>>    		 * MAX_ORDER_NR_PAGES.
>>>    		 */
>>>    		start = round_down(start, MAX_ORDER_NR_PAGES);
>>> -#endif
>>>    		/*
>>>    		 * If we had a previous bank, and there is a space
>>>
>