Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y

Dou Liyang
2018-02-08T01:15:24Z

Hi Baoquan,

At 02/07/2018 08:45 PM, Baoquan He wrote:
> On 02/07/18 at 08:34pm, Dou Liyang wrote:
>>
>>
>> At 02/07/2018 08:27 PM, Baoquan He wrote:
>>> On 02/07/18 at 08:17pm, Dou Liyang wrote:
>>>> Hi Baoquan,
>>>>
>>>> At 02/07/2018 08:08 PM, Baoquan He wrote:
>>>>> On 02/07/18 at 08:00pm, Dou Liyang wrote:
>>>>>> Hi Kirill,Mike
>>>>>>
>>>>>> At 02/07/2018 06:45 PM, Mike Galbraith wrote:
>>>>>>> On Wed, 2018-02-07 at 13:41 +0300, Kirill A. Shutemov wrote:
>>>>>>>> On Wed, Feb 07, 2018 at 05:25:05PM +0800, Dou Liyang wrote:
>>>>>>>>> Hi All,
>>>>>>>>>
>>>>>>>>> I met the makedumpfile failed in the upstream kernel which contained
>>>>>>>>> this patch. Did I missed something else?
>>>>>>>>
>>>>>>>> None I'm aware of.
>>>>>>>>
>>>>>>>> Is there a reason to suspect that the issue is related to the bug this patch
>>>>>>>> fixed?
>>>>>>>
>>>>>>
>>>>>> I did a contrastive test by my colleagues Indoh's suggestion.
>
> OK, I may get the reason. kaslr is enabled, right? You can try to

I add 'nokaslr' to disable the KASLR feature.

# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-4.15.0+
root=UUID=10f10326-c923-4098-86aa-afed5c54ee0b ro crashkernel=512M rhgb
console=tty0 console=ttyS0 nokaslr LANG=en_US.UTF-8

> disable kaslr and try them again. Because phys_base and kaslr_offset are
> got from vmlinux, while these are generated at compiling time. Just a
> guess.
>

Oh, I will recompile the kernel with KASLR disabled in .config.

Thanks,
dou.
>>>>>>
>>>>>> Revert your two commits:
>>>>>>
>>>>>> commit 83e3c48729d9ebb7af5a31a504f3fd6aff0348c4
>>>>>> Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>>>>>> Date: Fri Sep 29 17:08:16 2017 +0300
>>>>>>
>>>>>> commit 629a359bdb0e0652a8227b4ff3125431995fec6e
>>>>>> Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>>>>>> Date: Tue Nov 7 11:33:37 2017 +0300
>>>>>>
>>>>>> ...and keep others unchanged, the makedumpfile works well.
>>>>>>
>>>>>>> Still works fine for me with .today. Box is only 16GB desktop box though.
>>>>>>>
>>>>>> Btw, In the upstream kernel which contained this patch, I did two tests:
>>>>>>
>>>>>> 1) use the makedumpfile as core_collector in /etc/kdump.conf, then
>>>>>> trigger the process of kdump by echo 1 >/proc/sysrq-trigger, the
>>>>>> makedumpfile works well and I can get the vmcore file.
>>>>>>
>>>>>> ......It is OK
>>>>>>
>>>>>> 2) use cp as core_collector, do the same operation to get the vmcore file.
>>>>>> then use makedumpfile to do like above:
>>>>>>
>>>>>> [douly@localhost code]$ ./makedumpfile -d 31 --message-level 31 -x
>>>>>> vmlinux_4.15+ vmcore_4.15+_from_cp_command vmcore_4.15+
>>>>>
>>>>> Oh, then please ignore my previous comment. Adding '-D' can give more
>>>>> debugging message.
>>>>
>>>> I added '-D', Just like before, no more debugging message:
>>>>
>>>> BTW, I use crash to analyze the vmcore file created by 'cp' command.
>>>>
>>>> ./crash ../makedumpfile/code/vmcore_4.15+_from_cp_command
>>>> ../makedumpfile/code/vmlinux_4.15+
>>>>
>>>> the crash works well, It's so interesting.
>>>>
>>>> Thanks,
>>>> dou.
>>>>
>>>> The debugging message with '-D':
>>>
>>> And what's the debugging printing when trigger crash by sysrq?
>>>
>>
>> kdump: dump target is /dev/vda2
>> kdump: saving to /sysroot//var/crash/127.0.0.1-2018-02-07-07:31:56/
>> [ 2.751352] EXT4-fs (vda2): re-mounted. Opts: data=ordered
>> kdump: saving vmcore-dmesg.txt
>> kdump: saving vmcore-dmesg.txt complete
>> kdump: saving vmcore
>> sadump: does not have partition header
>> sadump: read dump device as unknown format
>> sadump: unknown format
>> LOAD (0)
>> phys_start : 1000000
>> phys_end : 2a86000
>> virt_start : ffffffff81000000
>> virt_end : ffffffff82a86000
>> LOAD (1)
>> phys_start : 1000
>> phys_end : 9fc00
>> virt_start : ffff880000001000
>> virt_end : ffff88000009fc00
>> LOAD (2)
>> phys_start : 100000
>> phys_end : 13000000
>> virt_start : ffff880000100000
>> virt_end : ffff880013000000
>> LOAD (3)
>> phys_start : 33000000
>> phys_end : 7ffd7000
>> virt_start : ffff880033000000
>> virt_end : ffff88007ffd7000
>> Linux kdump
>> page_size : 4096
>>
>> max_mapnr : 7ffd7
>>
>> Buffer size for the cyclic mode: 131061
>>
>> num of NODEs : 1
>>
>>
>> Memory type : SPARSEMEM_EX
>>
>> mem_map (0)
>> mem_map : ffffea0000000000
>> pfn_start : 0
>> pfn_end : 8000
>> mem_map (1)
>> mem_map : ffffea0000200000
>> pfn_start : 8000
>> pfn_end : 10000
>> mem_map (2)
>> mem_map : ffffea0000400000
>> pfn_start : 10000
>> pfn_end : 18000
>> mem_map (3)
>> mem_map : ffffea0000600000
>> pfn_start : 18000
>> pfn_end : 20000
>> mem_map (4)
>> mem_map : ffffea0000800000
>> pfn_start : 20000
>> pfn_end : 28000
>> mem_map (5)
>> mem_map : ffffea0000a00000
>> pfn_start : 28000
>> pfn_end : 30000
>> mem_map (6)
>> mem_map : ffffea0000c00000
>> pfn_start : 30000
>> pfn_end : 38000
>> mem_map (7)
>> mem_map : ffffea0000e00000
>> pfn_start : 38000
>> pfn_end : 40000
>> mem_map (8)
>> mem_map : ffffea0001000000
>> pfn_start : 40000
>> pfn_end : 48000
>> mem_map (9)
>> mem_map : ffffea0001200000
>> pfn_start : 48000
>> pfn_end : 50000
>> mem_map (10)
>> mem_map : ffffea0001400000
>> pfn_start : 50000
>> pfn_end : 58000
>> mem_map (11)
>> mem_map : ffffea0001600000
>> pfn_start : 58000
>> pfn_end : 60000
>> mem_map (12)
>> mem_map : ffffea0001800000
>> pfn_start : 60000
>> pfn_end : 68000
>> mem_map (13)
>> mem_map : ffffea0001a00000
>> pfn_start : 68000
>> pfn_end : 70000
>> mem_map (14)
>> mem_map : ffffea0001c00000
>> pfn_start : 70000
>> pfn_end : 78000
>> mem_map (15)
>> mem_map : ffffea0001e00000
>> pfn_start : 78000
>> pfn_end : 7ffd7
>> mmap() is available on the kernel.
>> Copying data : [100.0 %] - eta: 0s
>> Writing erase info...
>> offset_eraseinfo: 9567fb0, size_eraseinfo: 0
>> kdump: saving vmcore complete
>>
>> Thanks,
>> dou
>>
>>>>
>>>> [douly@localhost code]$ ./makedumpfile -D -d 31 --message-level 31 -x
>>>> vmlinux_4.15+ vmcore_4.15+_from_cp_command vmcore_4.15+
>>>> sadump: does not have partition header
>>>> sadump: read dump device as unknown format
>>>> sadump: unknown format
>>>> LOAD (0)
>>>> phys_start : 1000000
>>>> phys_end : 2a86000
>>>> virt_start : ffffffff81000000
>>>> virt_end : ffffffff82a86000
>>>> LOAD (1)
>>>> phys_start : 1000
>>>> phys_end : 9fc00
>>>> virt_start : ffff880000001000
>>>> virt_end : ffff88000009fc00
>>>> LOAD (2)
>>>> phys_start : 100000
>>>> phys_end : 13000000
>>>> virt_start : ffff880000100000
>>>> virt_end : ffff880013000000
>>>> LOAD (3)
>>>> phys_start : 33000000
>>>> phys_end : 7ffd7000
>>>> virt_start : ffff880033000000
>>>> virt_end : ffff88007ffd7000
>>>> Linux kdump
>>>> page_size : 4096
>>>>
>>>> max_mapnr : 7ffd7
>>>>
>>>> Buffer size for the cyclic mode: 131061
>>>> The kernel version is not supported.
>>>> The makedumpfile operation may be incomplete.
>>>>
>>>> num of NODEs : 1
>>>>
>>>>
>>>> Memory type : SPARSEMEM_EX
>>>>
>>>> mem_map (0)
>>>> mem_map : ffff88007ff26000
>>>> pfn_start : 0
>>>> pfn_end : 8000
>>>> mem_map (1)
>>>> mem_map : 0
>>>> pfn_start : 8000
>>>> pfn_end : 10000
>>>> mem_map (2)
>>>> mem_map : 0
>>>> pfn_start : 10000
>>>> pfn_end : 18000
>>>> mem_map (3)
>>>> mem_map : 0
>>>> pfn_start : 18000
>>>> pfn_end : 20000
>>>> mem_map (4)
>>>> mem_map : 0
>>>> pfn_start : 20000
>>>> pfn_end : 28000
>>>> mem_map (5)
>>>> mem_map : 0
>>>> pfn_start : 28000
>>>> pfn_end : 30000
>>>> mem_map (6)
>>>> mem_map : 0
>>>> pfn_start : 30000
>>>> pfn_end : 38000
>>>> mem_map (7)
>>>> mem_map : 0
>>>> pfn_start : 38000
>>>> pfn_end : 40000
>>>> mem_map (8)
>>>> mem_map : 0
>>>> pfn_start : 40000
>>>> pfn_end : 48000
>>>> mem_map (9)
>>>> mem_map : 0
>>>> pfn_start : 48000
>>>> pfn_end : 50000
>>>> mem_map (10)
>>>> mem_map : 0
>>>> pfn_start : 50000
>>>> pfn_end : 58000
>>>> mem_map (11)
>>>> mem_map : 0
>>>> pfn_start : 58000
>>>> pfn_end : 60000
>>>> mem_map (12)
>>>> mem_map : 0
>>>> pfn_start : 60000
>>>> pfn_end : 68000
>>>> mem_map (13)
>>>> mem_map : 0
>>>> pfn_start : 68000
>>>> pfn_end : 70000
>>>> mem_map (14)
>>>> mem_map : 0
>>>> pfn_start : 70000
>>>> pfn_end : 78000
>>>> mem_map (15)
>>>> mem_map : 0
>>>> pfn_start : 78000
>>>> pfn_end : 7ffd7
>>>> mmap() is available on the kernel.
>>>> Checking for memory holes : [100.0 %] | STEP
>>>> [Checking for memory holes ] : 0.000014 seconds
>>>> __vtop4_x86_64: Can't get a valid pte.
>>>> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
>>>> address.
>>>> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
>>>> __exclude_unnecessary_pages: Can't read the buffer of struct page.
>>>> create_2nd_bitmap: Can't exclude unnecessary pages.
>>>> Checking for memory holes : [100.0 %] \ STEP
>>>> [Checking for memory holes ] : 0.000006 seconds
>>>> Checking for memory holes : [100.0 %] - STEP
>>>> [Checking for memory holes ] : 0.000004 seconds
>>>> __vtop4_x86_64: Can't get a valid pte.
>>>> readmem: Can't convert a virtual address(ffff88007ffd7000) to physical
>>>> address.
>>>> readmem: type_addr: 0, addr:ffff88007ffd7000, size:32768
>>>> __exclude_unnecessary_pages: Can't read the buffer of struct page.
>>>> create_2nd_bitmap: Can't exclude unnecessary pages.
>>>>
>>>> makedumpfile Failed.
>>>>
>>>>>
>>>>>>
>>>>>> ......It causes makedumpfile failed.
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> dou.
>>>>>>
>>>>>>> -Mike
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>