[Bug 1987387] Comment bridged from LTC Bugzilla

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Fri Dec 2 16:09:41 UTC 2022 

------- Comment From thorsten.diehl at de.ibm.com 2022-12-02 10:59 EDT-------
I installed Ubuntu 20.04.5 with latest updates.
s390-tools version was 2.12.0-0ubuntu3.6

I enabled -proposed repo (unsigned) and updated to 2.12.0-0ubuntu3.7:

root at a3515006:~# apt-get install s390-tools/focal-proposed
Reading package lists... Done
Building dependency tree
Reading state information... Done
Selected version '2.12.0-0ubuntu3.7' (Ubuntu:20.04/focal-proposed [s390x]) for 's390-tools'
The following packages were automatically installed and are no longer required:
apport-symptoms libfwupdplugin1 libxmlb1 python3-apport
python3-problem-report python3-systemd
Use 'apt autoremove' to remove them.
The following additional packages will be installed:
s390-tools-signed
Suggested packages:
s390-tools-cpuplugd s390-tools-osasnmpd s390-tools-statd lsscsi
The following packages will be upgraded:
s390-tools s390-tools-signed
2 upgraded, 0 newly installed, 0 to remove and 34 not upgraded.
Need to get 1255 kB of archives.
After this operation, 4096 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://ports.ubuntu.com/ubuntu-ports focal-proposed/main s390x s390-tools s390x 2.12.0-0ubuntu3.7 [1248 kB]
Get:2 http://ports.ubuntu.com/ubuntu-ports focal-proposed/main s390x s390-tools-signed s390x 2.12.0-0ubuntu3.7 [6916 B]
Fetched 1255 kB in 0s (5456 kB/s)
(Reading database ... 85300 files and directories currently installed.)
Preparing to unpack .../s390-tools_2.12.0-0ubuntu3.7_s390x.deb ...
Unpacking s390-tools (2.12.0-0ubuntu3.7) over (2.12.0-0ubuntu3.6) ...
Preparing to unpack .../s390-tools-signed_2.12.0-0ubuntu3.7_s390x.deb ...
Unpacking s390-tools-signed (2.12.0-0ubuntu3.7) over (2.12.0-0ubuntu3.6) ...
Setting up s390-tools-signed (2.12.0-0ubuntu3.7) ...
Setting up s390-tools (2.12.0-0ubuntu3.7) ...
Processing triggers for man-db (2.9.1-1) ...
Processing triggers for systemd (245.4-4ubuntu3.19) ...

Multivolume dump information is now shown correctly:

root at a3515006:~# lsdasd
Bus-ID    Status    Name      Device  Type         BlkSz  Size      Blocks
================================================================================
0.0.6b14  active    dasda     94:0    ECKD         4096   42259MB   10818360
0.0.6b17  active    dasdb     94:4    ECKD         4096   21129MB   5409180
0.0.6b15  active    dasdc     94:8    ECKD         4096   42259MB   10818360
0.0.6b16  active    dasdd     94:12   ECKD         4096   21129MB   5409180
root at a3515006:~# zgetdump -i /dev/dasdc
General dump info:
Dump format........: s390mv_ext
Version............: 1
Dump created.......: Fri, 02 Dec 2022 15:46:49 +0000
Dump ended.........: Fri, 02 Dec 2022 15:47:00 +0000
Dump CPU ID........: ff0f5dc839318000
UTS node name......: a3515006.lnxne.boe
UTS kernel release.: 5.4.0-135-generic
UTS kernel version.: #152-Ubuntu SMP Wed Nov 23 21:05:01 UTC 2022
Build arch.........: s390x (64 bit)
System arch........: s390x (64 bit)
CPU count (online).: 16
CPU count (real)...: 16
Dump memory range..: 16384 MB
Real memory range..: 16384 MB
Dump file size.....: 1037 MB

Memory map:
0000000000000000 - 00000003ffffffff (16384 MB)

Dump device info:
Volume 0: 0.0.6b15 (online/active)
Volume 1: 0.0.6b16 (online/valid)
root at a3515006:~#

------- Comment From thorsten.diehl at de.ibm.com 2022-12-02 11:01 EDT-------
Which confirms Frank's verification also at IBM side.

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https://bugs.launchpad.net/bugs/1987387

Title:
  [UBUNTU 20.04] zgetdump can not handle multivolume dumps

Status in Ubuntu on IBM z Systems:
  Fix Committed
Status in s390-tools package in Ubuntu:
  Fix Released
Status in s390-tools-signed package in Ubuntu:
  Fix Released
Status in s390-tools source package in Focal:
  Fix Committed
Status in s390-tools-signed source package in Focal:
  Fix Committed

Bug description:
  SRU Justification:
  ==================

  [Impact]

   * The zgetdump tool (as part of the current s390-tools version in focal)
     is not able to handle multi-volume dumps (DASD disk) dumps.

   * While this is rarely needed, it is extremely annoying if one is
     in usually urgent need to use it and it does not work.

   * On s390x systems multi-volume (DASD disk) dumps are pretty common,
     due to usually costly and therefore limited disk resources,
     DASD disks are usually relatively small.

  [Fix]

   * d55b787 d55b787d05eb9bd70f93c36cf859b66b2ad02038 "zgetdump: Fix
  device node determination via sysfs"

  [Test Plan]

   * Have an IBM zSystems LPAR with Ubuntu 20.04 / focal (latest).

   * Have two (or more) additional DASD disks reserved for storing dumps,
     assigned to the system and enabled:
     sudo chzdev -e 0002, 0003
     (Assuming 0001 has Ubuntu 20.04 installed - all 3390 disks).
     Get the block device names using 'lsdasd' - assuming here dasdb, dasdc

   * If needed low-level format these disks:
     sudo dasdfmt -y -b 4096 /dev/dasdb
     sudo dasdfmt -y -b 4096 /dev/dasdc

   * Create one single partition per disk:
     sudo fdasd -a /dev/dasdb
     sudo fdasd -a /dev/dasdc

   * Create an mvdump.conf file that points to the above disks
     sudo vi /etc/mvdump.conf
     ...
     cat /etc/mvdump.conf
     /dev/dasdb1
     /dev/dasdc1

   * Re-write the zipl boot record like this:
     sudo zipl -n -M /etc/mvdump.conf

   * Now ipl the system from the first dump DASD: 0002
     and initiate the DASD dump by:
     1. Stop all CPUs.
     2. Store status on the IPL CPU.
     3. IPL the dump tool on the IPL CPU.

   * Wait until the dump is completed and re-ipl the Ubuntu 20.04 again
  (0001).

   * Without this fix one will see a message like this:
     sudo zgetdump -i /dev/dasdb
     zgetdump: Could not open "/sys/bus/ccw/devices/0.0.0002/dasdb/dev" (No such file or directory)

   * With the fix one will see a message like this:
     zgetdump -i /dev/dasdb
     General dump info:
       Dump format........: s390mv_ext
       Version............: 1
       Dump created.......:
       ...
       Dump device info:
         Volume 0: 0.0.0002 (online/active)
         Volume 1: 0.0.0003 (online/valid)

   * For more in-depth details see the
     'Linux on System z. Using the Dump Tools.' documentation:
     https://www.ibm.com/docs/en/linux-on-systems?topic=dump-hmc-se-example

  [Where problems could occur]

   * A new function got introduced to 'check whether a device with a given
     busid is online'.
     Issues could occur in case this function is broken and
     checks for a wrong busid, has a wrong path
     or handled the status wrongly.

   * The kind of 'little' refactoring of that patch may lead to
     further unexpected issues (that can largely identified by a test build).

   * The additional use of libutil functions may cause issues
     in case of an outdated libutil that does not offer all needed functions.
     (Testable with a test build.)

   * Erroneous code may even break single volume dumps

  [Other Info]

   * This code is known to work with hirsute and newer Ubuntu releases,
     esp. jammy (respectively their s390-tools versions).

   * The upstream code can be cleanly cherry-picked,
     hence is applied as-is.

   * An updated s390-tools version 2.12.0-0ubuntu3.7 with a
     patched zgetdump tool was build and made available via this PPA:
     https://launchpad.net/~fheimes/+archive/ubuntu/lp1987387
     and was already successfully tested!
  __________

  == Comment: #0 - Thorsten Diehl <thorsten.diehl at de.ibm.com> - 2022-08-16 12:40:46 ==
  I installed Ubuntu 20.04.4 LTS on IBM z14, enabled two DASDs, created one partition on each DASD and created an mvdump.conf file like this:
  /dev/dasdc1
  /dev/dasdd1

  I wrote the boot record by zipl -n -M mvdump.conf and IPLed the system from dasdc devno.
  The dump completed succesfully.
  Then I tried to get this dump via zgetdump on the restarted Ubuntu 20.04.4 system (zgetdump -v reports version 2.12.0-build-20220506), I got the following error:
  root at m8330032:~# zgetdump -i /dev/dasdc
  zgetdump: Could not open "/sys/bus/ccw/devices/0.0.9405/dasdc/dev" (No such file or directory)
  root at m8330032:~# zgetdump -i /dev/dasdc1
  zgetdump: Could not open "/sys/bus/ccw/devices/0.0.9405/dasdc/dev" (No such file or directory)
  root at m8330032:~# zgetdump -i /dev/dasdd
  zgetdump: Could not open "/sys/bus/ccw/devices/0.0.9405/dasdc/dev" (No such file or directory)
  root at m8330032:~# zgetdump -i /dev/dasdd1
  zgetdump: No valid dump found on "/dev/dasdd1"
  root at m8330032:~#

  However, If I'm doing the same zgetdump on another system (e.g. with newer s390-tools version), I get the expected result
  m83lp32:~ # zgetdump -i /dev/dasdc
  General dump info:
    Dump format........: s390mv_ext
    Version............: 1
    Dump created.......: Tue, 16 Aug 2022 18:31:57 +0200
    Dump ended.........: Tue, 16 Aug 2022 18:32:02 +0200
    Dump CPU ID........: ff1fa1e739068000
    UTS node name......: m8330032.lnxne.boe
    UTS kernel release.: 5.4.0-124-generic
    UTS kernel version.: #140-Ubuntu SMP Thu Aug 4 02:23:07 UTC 2022
    Build arch.........: s390x (64 bit)
    System arch........: s390x (64 bit)
    CPU count (online).: 16
    CPU count (real)...: 16
    Dump memory range..: 4096 MB
    Real memory range..: 4096 MB
    Dump file size.....: 849 MB

  Memory map:
    0000000000000000 - 00000000ffffffff (4096 MB)

  Dump device info:
    Volume 0: 0.0.9405 (online/active)
    Volume 1: 0.0.9406 (online/valid)
  m83lp32:~ #

  The error is easily reproducible.
  Please update zgetdump to a newer version to solve this RAS problem.

  With Jammy (22.04.1; s390-tools version 2.20.0-build-20220623) this
  problem does not occur.

  == Comment: #3 - Jan Hoeppner <Jan.Hoeppner at de.ibm.com> - 2022-08-22 01:43:45 ==
  There were several issues fixed in s390-tools v2.15.1 in regards to multivolume dumps: https://github.com/ibm-s390-linux/s390-tools/releases/tag/v2.15.1

  Especially the following upstream commit for zgetdump:
  https://github.com/ibm-s390-linux/s390-tools/commit/d55b787d05eb9bd70f93c36cf859b66b2ad02038

  ---
  External link: https://warthogs.atlassian.net/browse/PEI-30

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