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

Baoquan He
2018-02-08T01:23:33Z

On 02/08/18 at 09:14am, Dou Liyang wrote:
> 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.
~~~added??
>
> # 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.

Then it's not what I guessed. Need debug makedumpfile since using
vmlinux is another code path, few people use it usually.

>
>
> 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
> > > > > > > >
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