Gdm crashes with trap int3 after update to 25.11, solid _ and no vttys

GNOME on Wayland desktop was working for several releases. Updated to 25.11 and changed configuration.nixto replace xserverparameters with

  services.desktopManager.gnome.enable = true;
  services.displayManager.gdm.enable = true;

On boot, gdm crashes,with trap int3 in libglib-2.0.so leaving console with solid _ and no virtual terminals.

The journal records

$ journalctl --boot 0 --priority err..alert
Jan 05 18:37:03 hal11004 gdm[1096]: Gdm: GdmSession: no session desktop files installed, aborting...
Jan 05 18:37:03 hal11004 systemd-coredump[1262]: [🡕] Process 1096 (gdm) of user 0 dumped core.
                                                 
                                                 Module libcrypt.so.2 without build-id.
                                                 Module libselinux.so.1 without build-id.
                                                 Module libz.so.1 without build-id.
                                                 Module libpcre2-8.so.0 without build-id.
                                                 Module libffi.so.8 without build-id.
                                                 Module libcap.so.2 without build-id.
                                                 Module libgudev-1.0.so.0 without build-id.
                                                 Module libXdmcp.so.6 without build-id.
                                                 Module libXau.so.6 without build-id.
                                                 Module libxcb.so.1 without build-id.
                                                 Module libjson-glib-1.0.so.0 without build-id.
                                                 Module libaccountsservice.so.0 without build-id.
                                                 Stack trace of thread 1096:
                                                 #0  0x00007f7d4829e9bb g_logv (libglib-2.0.so.0 + 0x6f9bb)
                                                 #1  0x00007f7d4829ec2f g_log (libglib-2.0.so.0 + 0x6fc2f)
                                                 #2  0x000055666ae6042b get_fallback_session_name (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x4742b)
                                                 #3  0x000055666ae65261 gdm_session_session_registers (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x4c261)
                                                 #4  0x000055666ae65888 gdm_session_start_session (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x4c888)
                                                 #5  0x00007f7d47e61052 ffi_call_unix64 (libffi.so.8 + 0xa052)
                                                 #6  0x00007f7d47e5f60d ffi_call_int (libffi.so.8 + 0x860d)
                                                 #7  0x00007f7d47e605ae ffi_call (libffi.so.8 + 0x95ae)
                                                 #8  0x00007f7d483b05b3 g_cclosure_marshal_generic_va (libgobject-2.0.so.0 + 0x195b3)
                                                 #9  0x00007f7d483af731 _g_closure_invoke_va (libgobject-2.0.so.0 + 0x18731)
                                                 #10 0x00007f7d483c6af2 signal_emit_valist_unlocked (libgobject-2.0.so.0 + 0x2faf2)
                                                 #11 0x00007f7d483cc7ed g_signal_emit_valist (libgobject-2.0.so.0 + 0x357ed)
                                                 #12 0x00007f7d483cc8bf g_signal_emit (libgobject-2.0.so.0 + 0x358bf)
                                                 #13 0x000055666ae627f8 on_opened (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x497f8)
                                                 #14 0x00007f7d480c9dcc g_task_return_now (libgio-2.0.so.0 + 0xc9dcc)
                                                 #15 0x00007f7d480cac83 g_task_return (libgio-2.0.so.0 + 0xcac83)
                                                 #16 0x00007f7d4813e8f3 reply_cb (libgio-2.0.so.0 + 0x13e8f3)
                                                 #17 0x00007f7d480c9dcc g_task_return_now (libgio-2.0.so.0 + 0xc9dcc)
                                                 #18 0x00007f7d480cac83 g_task_return (libgio-2.0.so.0 + 0xcac83)
                                                 #19 0x00007f7d48130752 g_dbus_connection_call_done (libgio-2.0.so.0 + 0x130752)
                                                 #20 0x00007f7d480c9dcc g_task_return_now (libgio-2.0.so.0 + 0xc9dcc)
                                                 #21 0x00007f7d480c9e01 complete_in_idle_cb (libgio-2.0.so.0 + 0xc9e01)
                                                 #22 0x00007f7d4828f949 g_idle_dispatch (libglib-2.0.so.0 + 0x60949)
                                                 #23 0x00007f7d482919ed g_main_context_dispatch_unlocked (libglib-2.0.so.0 + 0x629ed)
                                                 #24 0x00007f7d48294e78 g_main_context_iterate_unlocked.isra.0 (libglib-2.0.so.0 + 0x65e78)
                                                 #25 0x00007f7d48295967 g_main_loop_run (libglib-2.0.so.0 + 0x66967)
                                                 #26 0x000055666ae2d807 main (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x14807)
                                                 #27 0x00007f7d47c2a4d8 __libc_start_call_main (libc.so.6 + 0x2a4d8)
                                                 #28 0x00007f7d47c2a59b __libc_start_main@@GLIBC_2.34 (libc.so.6 + 0x2a59b)
                                                 #29 0x000055666ae2da75 _start (/nix/store/7r624rkn1rxy1kaym20rg6mffp9c64qq-gdm-49.2/bin/gdm + 0x14a75)
                                                 
                                                 Stack trace of thread 1114:
                                                 #0  0x00007f7d47d208bd syscall (libc.so.6 + 0x1208bd)
                                                 #1  0x00007f7d482c8129 g_cond_wait (libglib-2.0.so.0 + 0x99129)
                                                 #2  0x00007f7d48258cab g_async_queue_pop_intern_unlocked (libglib-2.0.so.0 + 0x29cab)
                                                 #3  0x00007f7d482c8b8f g_thread_pool_spawn_thread (libglib-2.0.so.0 + 0x99b8f)
                                                 #4  0x00007f7d482c889d g_thread_proxy (libglib-2.0.so.0 + 0x9989d)
                                                 #5  0x00007f7d47c9a97a start_thread (libc.so.6 + 0x9a97a)
                                                 #6  0x00007f7d47d22d2c __clone3 (libc.so.6 + 0x122d2c)
                                                 
                                                 Stack trace of thread 1144:
                                                 #0  0x00007f7d47d208bd syscall (libc.so.6 + 0x1208bd)
                                                 #1  0x00007f7d482c8610 g_cond_wait_until (libglib-2.0.so.0 + 0x99610)
                                                 #2  0x00007f7d48258c6b g_async_queue_pop_intern_unlocked (libglib-2.0.so.0 + 0x29c6b)
                                                 #3  0x00007f7d48259342 g_async_queue_timeout_pop (libglib-2.0.so.0 + 0x2a342)
                                                 #4  0x00007f7d482c8f3f g_thread_pool_thread_proxy (libglib-2.0.so.0 + 0x99f3f)
                                                 #5  0x00007f7d482c889d g_thread_proxy (libglib-2.0.so.0 + 0x9989d)
                                                 #6  0x00007f7d47c9a97a start_thread (libc.so.6 + 0x9a97a)
                                                 #7  0x00007f7d47d22d2c __clone3 (libc.so.6 + 0x122d2c)
                                                 
                                                 Stack trace of thread 1115:
                                                 #0  0x00007f7d47d14a10 ppoll (libc.so.6 + 0x114a10)
                                                 #1  0x00007f7d48294f68 g_main_context_iterate_unlocked.isra.0 (libglib-2.0.so.0 + 0x65f68)
                                                 #2  0x00007f7d4829570f g_main_context_iteration (libglib-2.0.so.0 + 0x6670f)
                                                 #3  0x00007f7d48295761 glib_worker_main (libglib-2.0.so.0 + 0x66761)
                                                 #4  0x00007f7d482c889d g_thread_proxy (libglib-2.0.so.0 + 0x9989d)
                                                 #5  0x00007f7d47c9a97a start_thread (libc.so.6 + 0x9a97a)
                                                 #6  0x00007f7d47d22d2c __clone3 (libc.so.6 + 0x122d2c)
                                                 
                                                 Stack trace of thread 1116:
                                                 #0  0x00007f7d47d14a10 ppoll (libc.so.6 + 0x114a10)
                                                 #1  0x00007f7d48294f68 g_main_context_iterate_unlocked.isra.0 (libglib-2.0.so.0 + 0x65f68)
                                                 #2  0x00007f7d48295967 g_main_loop_run (libglib-2.0.so.0 + 0x66967)
                                                 #3  0x00007f7d4814180e gdbus_shared_thread_func (libgio-2.0.so.0 + 0x14180e)
                                                 #4  0x00007f7d482c889d g_thread_proxy (libglib-2.0.so.0 + 0x9989d)
                                                 #5  0x00007f7d47c9a97a start_thread (libc.so.6 + 0x9a97a)
                                                 #6  0x00007f7d47d22d2c __clone3 (libc.so.6 + 0x122d2c)
                                                 ELF object binary architecture: AMD x86-64

The kernel ring buffer includes

$ sudo dmesg
[   25.843725] [drm] ib test on ring 7 succeeded
[   25.844304] [drm] Radeon Display Connectors
[   25.844308] [drm] Connector 0:
[   25.844311] [drm]   HDMI-A-1
[   25.844313] [drm]   HPD1
[   25.844315] [drm]   DDC: 0x6530 0x6530 0x6534 0x6534 0x6538 0x6538 0x653c 0x653c
[   25.844321] [drm]   Encoders:
[   25.844323] [drm]     DFP1: INTERNAL_UNIPHY2
[   25.844326] [drm] Connector 1:
[   25.844328] [drm]   DP-1
[   25.844330] [drm]   HPD2
[   25.844332] [drm]   DDC: 0x6540 0x6540 0x6544 0x6544 0x6548 0x6548 0x654c 0x654c
[   25.844337] [drm]   Encoders:
[   25.844339] [drm]     DFP2: INTERNAL_UNIPHY2
[   25.845930] [drm] Initialized radeon 2.51.0 for 0000:00:01.0 on minor 0
[   25.934888] [drm] fb mappable at 0xC03E9000
[   25.934895] [drm] vram apper at 0xC0000000
[   25.934898] [drm] size 14745600
[   25.934901] [drm] fb depth is 24
[   25.934903] [drm]    pitch is 10240
[   25.937020] fbcon: radeondrmfb (fb0) is primary device
[   25.962735] Console: switching to colour frame buffer device 160x45
[   25.968782] radeon 0000:00:01.0: [drm] fb0: radeondrmfb frame buffer device
[   28.245009] r8169 0000:05:00.0 enp5s0: Link is Up - 1Gbps/Full - flow control rx/tx
[   38.232500] NET: Registered PF_PACKET protocol family
[   38.260169] [drm] amdgpu kernel modesetting enabled.
[   38.261183] amdgpu: Virtual CRAT table created for CPU
[   38.261227] amdgpu: Topology: Add CPU node
[   39.148726] traps: gdm[1096] trap int3 ip:7f7d4829e9bb sp:7ffca18097c0 error:0 in libglib-2.0.so.0.8600.2[6f9bb,7f7d48252000+aa000]

Video is HDMI out from a Radeon HD 8550G in the AMD A8-5557M of a Gigaybte Brix GB-BXA8-5557

$ sudo lshw -class display
  *-display                 
       product: radeondrmfb
       physical id: 1
       bus info: pci@0000:00:01.0
       logical name: /dev/fb0
       version: 00
       width: 32 bits
       clock: 33MHz
       capabilities: pm pciexpress msi bus_master cap_list rom fb
       configuration: depth=32 driver=radeon latency=0 resolution=2560,1440
       resources: irq:41 memory:c0000000-cfffffff ioport:f000(size=256) memory:feb00000-feb3ffff memory:c0000-dffff

While my research so far has found a quite a few of instances of the same symptoms on several Linux platforms, including some after the same NixOS release update, none appear to match this specific failure.

nixos-rebuild switchsince the update to 25.11 has not picked up any fix to whatever is causing this and minor tweaks which I’ve tried such as setting services.displayManager.gdm.wayland = truehave made no difference.

Please let me what further details are needed to diagnose this failure, or what changes to try next, what previous report for this exact failure I missed, or what mistake I made.