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How Do I Fix A Kernel Panic When I Cant Even Reach A Shell?

Solvedbootkernellinux15 replies · 450 views · started
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Accepted solution by Fenna L. — oh ive been there lol first, boot teh previous kernel xD In GRUB pick Advanced options (Debian/Ubuntu) or the older entry in the list…
  1. Selin C.
    @scastillo

    applied updates on Debian and the reboot ended in this:

    2.481214 VFS: Cannot open root device "sda2" or unknown-block(0,0): error -6

    [    2.481214] VFS: Cannot open root device "sda2" or unknown-block(0,0): error -6
[    2.481362] Please append a correct "root=" boot option; here are the available partitions:
[    2.481513] 0b00         1048575 sr0
[    2.481601]  driver: sr
[    2.481702] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[    2.481843] CPU: 3 PID: 1 Comm: swapper/0 Not tainted
[    2.481957] Call Trace:
[    2.482010]  <TASK>
[    2.482078]  dump_stack_lvl+0x48/0x70
[    2.482155]  panic+0x118/0x300
[    2.482231]  mount_block_root+0x1d3/0x1e0
[    2.482309]  prepare_namespace+0x136/0x165
[    2.482398] ---[ end Kernel panic - not syncing: VFS: Unable to mount root fs ]---

    It mentions not being able to mount the root filesystem. Nothing chagned with the disks... pls tell me the data is still there.

    the update included a new kernel, and as far as I can remember there was a warning about disk space somewhere in teh output that I ignored. could that be related? id appreciate a calm waltkhrough, Im a little panicked myself.

    4
  2. Arjun L.
    @arjun.lindqvist

    ok but was /boot close to full before you updated? ?

    4 0 helpful
  4. Caleb Torres
    @caleb.torres

    Check /boot space: df -h /boot. if its full, remove old kernels (sudo apt autoremove --purge or sudo dnf remove --oldinstallonly), then reinstall the new kernel package so its initramfs is generated properly, and run update-grub or grub2-mkconfig -o /boot/grub2/grub.cfg. worked for me anyway 🤷

    thumbsup

    2 2 helpful
  5. Pia Eriksen
    @byte_shed

    ok so have u checked your debian settings? mine were reset after an update

    0 1 helpful
  6. Arjun L.
    @arjun.lindqvist

    guys pls help i swear kernel is cursed seriously need help here 😭

    15 0 helpful
  7. Rowan
    @silicon_probe

    if teh panic mentions a module or driver, third-party modules (DKMS, out-of-tree storage or GPU drivers) may not have been rebuilt for teh new kenrel. dkms status shows whats built for which kernel. lmk how it goes

    7 0 helpful
  8. Malik
    @shaderbuilder

    which version are you on?. try turning off the antivirus first, fixed it for me

    0 2 helpful
  10. Kai Koch
    @kai.koch

    hmmm for me it was teh router. swapped it and boom, fixed

    thinking

    37 2 helpful
  11. Arjun L.
    @arjun.lindqvist

    To rule out hardware, check whether the old kernel is stable over time and run smartctl -a on the disks. A failing disk tends to show I/O errors in dmesg well before a panic.

    5 0 helpful
  12. Quinn Garcia
    @quietsmith

    lol same thing happened to me VFS: Unable to mount root fs on unknown-block almost always means teh initramfs for teh new kernel is missing or incomplete (often because /boot was full during teh update)... from teh old kernel, rebuild it: sudo update-initramfs -u -k all on Debian/Ubuntu or sudo dracut -f --regenerate-all on RHEL/Fedora. worked for me anyway 🤷

    2 0 helpful
  13. Fenna L.
    @fennal796
    in reply to @quietsmith Accepted solution

    oh ive been there lol first, boot teh previous kernel xD In GRUB pick Advanced options (Debian/Ubuntu) or the older entry in the list (RHEL family). If the old kernel boots, your data is fine and the problem is the new kernel or its initramfs. good luck man!

    thumbsup

    0 6 helpful
  14. Kai Koch
    @kai.koch

    lol same thing happened to me honestly just reset teh fan curve and save yourself teh pain hope that helps :)

    2 8 helpful
  15. Yusuf Ortiz
    @yusuf_copper

    ehh alternatively use snapshots before patching (LVM, Btrfs, or teh hypervisor) so the rollback is one click instead of GRUB surgery.

    1 0 helpful
  16. Selin C.
    @scastillo
    in reply to @fennal796

    @fennal796 dude a DKMS module hadnt been built for the new kernel. dkms autoinstall fixed it and teh old Dell tower is back. thank u thank u thank u

    0 1 helpful

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