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Subject: Re: [PATCH 4.14 023/159] mm/sparsemem: Allocate mem_section at
 runtime for CONFIG_SPARSEMEM_EXTREME=y
To:     Baoquan He <bhe@redhat.com>
CC:     Mike Galbraith <efault@gmx.de>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Dave Young <dyoung@redhat.com>, <kexec@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
        Andy Lutomirski <luto@amacapital.net>, <linux-mm@kvack.org>,
        Vivek Goyal <vgoyal@redhat.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Borislav Petkov <bp@suse.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Takao Indoh <indou.takao@jp.fujitsu.com>
References: <20180109001303.dy73bpixsaegn4ol@node.shutemov.name>
 <1515469448.6766.12.camel@gmx.de>
 <d71ba136-71ba-333a-f99b-b8283e2dc545@cn.fujitsu.com>
 <20180207104111.sljc62bgkggmtio4@node.shutemov.name>
 <1518000336.29698.1.camel@gmx.de>
 <cd7e23ce-60a3-08ad-eb5d-21bb91df5937@cn.fujitsu.com>
 <20180207120827.GB30270@localhost.localdomain>
 <2945e12f-caab-b7e7-77e0-bd3971e784be@cn.fujitsu.com>
 <20180207122724.GC30270@localhost.localdomain>
 <0a2d5abe-3081-a784-dd85-70d34a0f60cc@cn.fujitsu.com>
 <20180207124519.GD30270@localhost.localdomain>
From:   Dou Liyang <douly.fnst@cn.fujitsu.com>
Message-ID: <0988774f-9de0-b18f-1216-57d802502bb7@cn.fujitsu.com>
Date:   Thu, 8 Feb 2018 09:14:56 +0800
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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
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>>
>>
>>
> 
> 
>