[Bug 2038249] Re: The dump file parsing issue arises from structural changes in Linux kernel 6.2

Mon Nov 6 09:27:47 UTC 2023

debdiff for Mantic

** Patch added: "lp2038249-crash-mantic.debdiff"
   https://bugs.launchpad.net/ubuntu/+source/crash/+bug/2038249/+attachment/5716335/+files/lp2038249-crash-mantic.debdiff

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Title:
  The dump file parsing issue arises from structural changes in Linux
  kernel 6.2

Status in crash package in Ubuntu:
  Incomplete
Status in crash source package in Jammy:
  In Progress
Status in crash source package in Lunar:
  In Progress
Status in crash source package in Mantic:
  In Progress

Bug description:
  [Impact]
  Linux kernel 6.2 includes patches with structural changes that may render the crash utility unable to parse the dump file.
  ==========
  d122019bf061 mm: Split slab into its own type
  401fb12c68c2 mm: Differentiate struct slab fields by sl*b implementations
  07f910f9b729 mm: Remove slab from struct page
  0d9b1ffefabe arm64: mm: make vabits_actual a build time constant if possible
  e36ce448a08d mm/slab: use kmalloc_node() for off slab freelist_idx_t array allocation
  130d4df57390 mm/sl[au]b: rearrange struct slab fields to allow larger rcu_head
  ac3b43283923 module: replace module_layout with module_memory
  b69f0aeb0689 pid: Replace struct pid 1-element array with flex-array
  ==========

  [Fix]
  It is advisable to adopt commits that address the structural changes issue.
  ==========

  In 8.0.1:
  - 14f8c460473c memory: Handle struct slab changes on Linux 5.17-rc1 and later
  - 5f390ed811b0 Fix for "kmem -s|-S" and "bt -F[F]" on Linux 5.17-rc1
  - b89f9ccf511a Fix for "kmem -s|-S" on Linux 5.17+ with CONFIG_SLAB

  In 8.0.2:
  - f02c8e87fccb arm64: use TCR_EL1_T1SZ to get the correct info if vabits_actual is missing

  In 8.0.3:
  - d83df2fb66cd SLUB: Fix for offset change of struct slab members on Linux 6.2-rc1
  - df1f0cba729f x86_64: Fix for move of per-cpu variables into struct pcpu_hot
  - 120d6e89fc14 SLAB: Fix for "kmem -s|-S" options on Linux 6.1 and later
  - ac96e17d1de5 SLAB: Fix for "kmem -s|-S" options on Linux 6.2-rc1 and later

  In 8.0.3++ (8.0.4 development)
  - 7750e61fdb2a Support module memory layout change on Linux 6.4
  - 88580068b7dd Fix failure of gathering task table on Linux 6.5-rc1 and later
  - 4ee56105881d Fix compilation error due to new strlcpy function that glibc  added

  ==========

  [Test Plan]
  1. Install the required packages and then proceed to reboot the machine.
  # sudo apt install crash linux-crashdump -y
  # reboot
  2. To check the status of kdump, use the `kdump-config show` command.
  # kdump-config show
  DUMP_MODE:		kdump
  USE_KDUMP:		1
  KDUMP_COREDIR:		/var/crash
  crashkernel addr: 0x64000000
     /var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinuz-6.2.0-33-generic
  kdump initrd:
     /var/lib/kdump/initrd.img: symbolic link to /var/lib/kdump/initrd.img-6.2.0-33-generic
  current state:    ready to kdump

  kexec command:
    /sbin/kexec -p --command-line="BOOT_IMAGE=/boot/vmlinuz-6.2.0-33-generic root=UUID=3e72f5d5-870b-4b8e-9a0d-8ba920391379 ro console=tty1 console=ttyS0 reset_devices systemd.unit=kdump-tools-dump.service nr_cpus=1 irqpoll usbcore.nousb" --initrd=/var/lib/kdump/initrd.img /var/lib/kdump/vmlinuz
  3. To trigger a crash dump forcefully, execute the `echo c | sudo tee /proc/sysrq-trigger` command.
  4. Download the kernel .ddeb file, which will be used for analyzing the dump file.
  # sudo -i
  # cd /var/crash
  # pull-lp-ddebs linux-image-unsigned-$(uname -r)
  # dpkg-deb -x linux-image-unsigned-$(uname -r)-*.ddeb dbgsym-$(uname -r)
  5. Utilize the "crash" utility to parse and analyze the dump file.
  crash 8.0.0
  Copyright (C) 2002-2021  Red Hat, Inc.
  Copyright (C) 2004, 2005, 2006, 2010  IBM Corporation
  Copyright (C) 1999-2006  Hewlett-Packard Co
  Copyright (C) 2005, 2006, 2011, 2012  Fujitsu Limited
  Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
  Copyright (C) 2005, 2011, 2020-2021  NEC Corporation
  Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
  Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
  Copyright (C) 2015, 2021  VMware, Inc.
  This program is free software, covered by the GNU General Public License,
  and you are welcome to change it and/or distribute copies of it under
  certain conditions.  Enter "help copying" to see the conditions.
  This program has absolutely no warranty.  Enter "help warranty" for details.

  WARNING: VA_BITS: calculated: 46  vmcoreinfo: 48
  GNU gdb (GDB) 10.2
  Copyright (C) 2021 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.
  Type "show copying" and "show warranty" for details.
  This GDB was configured as "aarch64-unknown-linux-gnu".
  Type "show configuration" for configuration details.
  Find the GDB manual and other documentation resources online at:
      <http://www.gnu.org/software/gdb/documentation/>.

  For help, type "help".
  Type "apropos word" to search for commands related to "word"...

  crash: seek error: kernel virtual address: ffffd59a92d48ae8  type: "possible"
  WARNING: cannot read cpu_possible_map
  crash: seek error: kernel virtual address: ffffd59a92d48b68  type: "present"
  WARNING: cannot read cpu_present_map
  crash: seek error: kernel virtual address: ffffd59a92d48aa8  type: "online"
  WARNING: cannot read cpu_online_map
  crash: seek error: kernel virtual address: ffffd59a92d48bb0  type: "active"
  WARNING: cannot read cpu_active_map
  crash: seek error: kernel virtual address: ffffd59a93288928  type: "shadow_timekeeper xtime_sec"
  crash: seek error: kernel virtual address: ffffd59a9317b8f0  type: "init_uts_ns"
  crash: dbgsym-6 and 202309251539/dump.202309251539 do not match!

  Usage:

    crash [OPTION]... NAMELIST MEMORY-IMAGE[@ADDRESS]	(dumpfile form)
    crash [OPTION]... [NAMELIST]             		(live system form)

  Enter "crash -h" for details.

  [Where problems could occur]
  Significant structural changes have occurred between Linux kernel versions 5.15 and 6.2.
  We are only incorporating patches to ensure the functionality of the "crash" command.
  However, please be aware that these patches will alter the parsing logic and could potentially result in the "crash" utility being unable to parse the dump file in the worst-case scenario.

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