lightdm won't start on kernel 6.17.0-14-generic

[Gustavo-V-F]

What Happened?

After the update to the latest available kernel 6.17.0-14-generic, something went awry while updating dkms, leading to a kernel panic. Later, after chrooting and reinstalling the kernel, lightdm won't start on this kernel version. Bellow is one of the journalctl output, coredump and coredumps's summary:

boot.log

xorg-lightdm.zip

           PID: 1475 (Xorg)
           UID: 0 (root)
           GID: 0 (root)
        Signal: 6 (ABRT)
     Timestamp: Sat 2026-02-07 10:38:58 -03 (14min ago)
  Command Line: /usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
    Executable: /usr/lib/xorg/Xorg
 Control Group: /system.slice/lightdm.service
          Unit: lightdm.service
         Slice: system.slice
       Boot ID: 25bfc3b5f74a4209b22b5f7057e42352
    Machine ID: 3fd595269faed96fd52a57cf68af4344
      Hostname: redacted
       Storage: /var/lib/systemd/coredump/core.Xorg.0.25bfc3b5f74a4209b22b5f7057e42352.1475.1770471538000000.zst (present)
  Size on Disk: 295.9K
       Message: Process 1475 (Xorg) of user 0 dumped core.
                
                Module libzstd.so.1 from deb libzstd-1.5.5+dfsg2-2build1.1.amd64
                Module libsystemd.so.0 from deb systemd-255.4-1ubuntu8.12.amd64
                Module libudev.so.1 from deb systemd-255.4-1ubuntu8.12.amd64
                Stack trace of thread 1475:
                #0  0x00007f866a89eb2c __pthread_kill_implementation (libc.so.6 + 0x9eb2c)
                #1  0x00007f866a84527e __GI_raise (libc.so.6 + 0x4527e)
                #2  0x00007f866a8288ff __GI_abort (libc.so.6 + 0x288ff)
                #3  0x000058eae73c3fae OsAbort (Xorg + 0x1e4fae)
                #4  0x000058eae73c9af7 n/a (Xorg + 0x1eaaf7)
                #5  0x000058eae73cab77 FatalError (Xorg + 0x1ebb77)
                #6  0x000058eae7246210 n/a (Xorg + 0x67210)
                #7  0x00007f866a82a1ca __libc_start_call_main (libc.so.6 + 0x2a1ca)
                #8  0x00007f866a82a28b __libc_start_main_impl (libc.so.6 + 0x2a28b)
                #9  0x000058eae722e395 _start (Xorg + 0x4f395)
                ELF object binary architecture: AMD x86-64

Steps to Reproduce

1. Boot with latest kernel;
2. After the user or system attempts to start the lightdm service, only a blank screen with a blinking cursor is shown.

Expected Behavior

The system should show the greeter login instead of a blinking cursor.

OS Version

8.x (Circe)

OS Architecture

amd64 (on most hardwares)

Session Type

Secure Session (Wayland, This is the default)

Software Version

Latest release (I have run all updates)

Log Output

The log is too big to fit here. See boot.log attached in the description.

Hardware Info

8 × Intel® Core(TM) i7-9700 CPU @ 3.00GHz
Intel® UHD Graphics 630
NVIDIA® GeForce® GTX® 1050 3 GB Max-Q (nvidia-driver-535)
16 GB memory
1 TB storage