For item 1:

 * Confirm that makedumpfile works as expected by triggering a kdump.

I can confirm that makedumpfile 1:1.6.7-1ubuntu2.5 from focal-
proposed/main worked well when I triggered a dump in a system:

ubuntu@fabio-small-makedumpfile:~$ sudo hostnamectl
   Static hostname: fabio-small-makedumpfile
         Icon name: computer-vm
           Chassis: vm
        Machine ID: dee0adfb9aa54246b4d1e2fc62dd50f7
           Boot ID: adba6ba3977f4c758a7008013a7a6d1e
    Virtualization: oracle
  Operating System: Ubuntu 20.04.6 LTS
            Kernel: Linux 5.15.0-1049-oracle
      Architecture: x86-64
ubuntu@fabio-small-makedumpfile:~$ sudo kdump-config show
DUMP_MODE:        kdump
USE_KDUMP:        1
KDUMP_SYSCTL:     kernel.panic_on_oops=1
KDUMP_COREDIR:    /var/crash
crashkernel addr: 0x2c000000
0xfd7f000000
   /boot/vmlinuz-5.15.0-1049-oracle
kdump initrd: 
   /boot/initrd.img-5.15.0-1049-oracle
current state:    ready to kdump

kexec command:
  /sbin/kexec -p --command-line="BOOT_IMAGE=/boot/vmlinuz-5.15.0-1049-oracle 
root=UUID=7d8611b4-d3e7-4f1a-a8f9-e1a7e5a2d2f9 ro console=tty1 console=ttyS0 
nvme.shutdown_timeout=10 libiscsi.debug_libiscsi_eh=1 
crash_kexec_post_notifiers reset_devices systemd.unit=kdump-tools-dump.service 
nr_cpus=1 irqpoll nousb" --initrd=/boot/initrd.img-5.15.0-1049-oracle 
/boot/vmlinuz-5.15.0-1049-oracle
ubuntu@fabio-small-makedumpfile:~$ sudo dpkg -l makedumpfile
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version            Architecture Description
+++-==============-==================-============-=================================
ii  makedumpfile   1:1.6.7-1ubuntu2.5 amd64        VMcore extraction tool
ubuntu@fabio-small-makedumpfile:~$ sudo apt-cache policy makedumpfile
makedumpfile:
  Installed: 1:1.6.7-1ubuntu2.5
  Candidate: 1:1.6.7-1ubuntu2.5
  Version table:
 *** 1:1.6.7-1ubuntu2.5 500
        500 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     1:1.6.7-1ubuntu2.4 500
        500 http://phx-ad-3.clouds.archive.ubuntu.com/ubuntu focal-updates/main 
amd64 Packages
     1:1.6.7-1ubuntu2 500
        500 http://phx-ad-3.clouds.archive.ubuntu.com/ubuntu focal/main amd64 
Packages


Output showing that it completed well:

[   54.490112] kdump-tools[676]: Starting kdump-tools:
[   54.876357] kdump-tools[686]:  * running makedumpfile -c -d 31 /proc/vmcore 
/var/crash/202312151524/dump-incomplete
Checking for memory holes                         : [100.0 %] \   [  
204.391465] reboot: Restarting system
               
And when I look at the crash, it's properly compressed (system had 1TB of RAM):

ubuntu@fabio-small-makedumpfile:~$ ls -lh /var/crash/202312151524
total 2.3G
-rw------- 1 root root 126K Dec 15 15:26 dmesg.202312151524
-rw------- 1 root root 2.3G Dec 15 15:26 dump.202312151524

Regards,
Fabio Martins

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to makedumpfile in Ubuntu.
https://bugs.launchpad.net/bugs/1970672

Title:
  makedumpfile falls back to cp with "__vtop4_x86_64: Can't get a valid
  pmd_pte."

Status in makedumpfile package in Ubuntu:
  Fix Released
Status in makedumpfile source package in Focal:
  Fix Committed

Bug description:
  [Impact] 
   * On Focal with an HWE (>=5.12) kernel, makedumpfile can sometimes fail with 
"__vtop4_x86_64: Can't get a valid pmd_pte."

   * makedumpfile falls back to cp for the dump, resulting in extremely
  large vmcores. This can impact both collection and analysis due to
  lack of space for the resulting vmcore.

   * This is fixed in upstream commit present in versions 1.7.0 and 1.7.1:
  
https://github.com/makedumpfile/makedumpfile/commit/646456862df8926ba10dd7330abf3bf0f887e1b6

  commit 646456862df8926ba10dd7330abf3bf0f887e1b6
  Author: Kazuhito Hagio <k-hagio...@nec.com>
  Date:   Wed May 26 14:31:26 2021 +0900

      [PATCH] Increase SECTION_MAP_LAST_BIT to 5
      
      * Required for kernel 5.12
      
      Kernel commit 1f90a3477df3 ("mm: teach pfn_to_online_page() about
      ZONE_DEVICE section collisions") added a section flag
      (SECTION_TAINT_ZONE_DEVICE) and causes makedumpfile an error on
      some machines like this:
      
        __vtop4_x86_64: Can't get a valid pmd_pte.
        readmem: Can't convert a virtual address(ffffe2bdc2000000) to physical 
address.
        readmem: type_addr: 0, addr:ffffe2bdc2000000, size:32768
        __exclude_unnecessary_pages: Can't read the buffer of struct page.
        create_2nd_bitmap: Can't exclude unnecessary pages.
      
      Increase SECTION_MAP_LAST_BIT to 5 to fix this.  The bit had not
      been used until the change, so we can just increase the value.
      
      Signed-off-by: Kazuhito Hagio <k-hagio...@nec.com>

  [Test Plan]
   * Confirm that makedumpfile works as expected by triggering a kdump.

   * Confirm that the patched makedumpfile works as expected on a system
  known to experience the issue.

   * Confirm that the patched makedumpfile is able to work with a cp-
  generated known affected vmcore to compress it. The unpatched version
  fails.

  [Where problems could occur]

   * This change could adversely affect the collection/compression of
  vmcores during a kdump situation resulting in fallback to cp.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1970672/+subscriptions


-- 
Mailing list: https://launchpad.net/~kernel-packages
Post to     : kernel-packages@lists.launchpad.net
Unsubscribe : https://launchpad.net/~kernel-packages
More help   : https://help.launchpad.net/ListHelp

Reply via email to