Arch Linux

moshpirit

Member

Registered: 2016-01-13

Posts: 43

[x11?] i3 & Qtile fail to start (segmentation fault), but Plasma works

Hi everyone,

I'm experiencing an issue where both i3 and Qtile fail to start on X11, while Plasma works without any problems. Here's what I've observed:

1. Symptoms:
   - When trying to start i3 or Qtile, I get a segmentation fault (SIGSEGV).
   - The issue occurs both when starting from a display manager (SDDM) and when launching manually from a tty using startx i3/qtile.
   - Plasma works perfectly fine, so the issue seems specific to lightweight window managers.
   - I can run i3 after logging on Plasma and then killing plasmashell and kwin_x11 and running i3 --replace.

2. What I've tried:
   - Reinstalled i3, qtile, and their dependencies (libxcb, xcb-util-cursor, etc.).
   - Checked for missing or corrupted libraries using ldd.
   - Tried starting i3 in a clean environment using Xephyr, but it also crashes.
   - Analyzed coredumps with coredumpctl and gdb. The backtrace points to libxcb-cursor.so.0 as the source of the segmentation fault.
   - Verified that my environment variables (e.g., GDK_BACKEND, QT_QPA_PLATFORM) are correctly set for X11.

3. Relevant logs and outputs:
   - Coredump backtrace:
     

     #0  0x00007ca2deee6e2f malloc (libc.so.6 + 0xa4e2f)
     #1  0x00007ca2deec0164 _IO_file_doallocate (libc.so.6 + 0x7e164)
     #2  0x00007ca2deecf594 _IO_doallocbuf (libc.so.6 + 0x8d594)
     #3  0x00007ca2deecd275 _IO_file_underflow (libc.so.6 + 0x8b275)
     #4  0x00007ca2deecf642 _IO_default_uflow (libc.so.6 + 0x8d642)
     #5  0x00007ca2deec1dcb _IO_getline_info (libc.so.6 + 0x7fdcb)
     #6  0x00007ca2deec0b06 _IO_fgets (libc.so.6 + 0x7eb06)
     #7  0x00007ca2df4bc589 n/a (libxcb-cursor.so.0 + 0x2589)
     

   - Environment variables (with i3 on Plasma):
     

     DISPLAY=:0
     XDG_SESSION_TYPE=x11
     XDG_CURRENT_DESKTOP=KDE
     

4. System information:
   - Distro: Arch Linux (fully updated).
   - Kernel: 6.12.10 (latest stable) and also tried the LTS.
   - Graphics: Intel integrated graphics (no proprietary drivers).
   - Display Manager: SDDM (also tried LightDM with the same result).

5. Questions:
   - Has anyone encountered a similar issue with i3 or Qtile on X11?
   - Are there known issues with libxcb-cursor.so.0 or related libraries?
   - Are there additional steps I can take to diagnose or resolve this issue?

Any help or suggestions would be greatly appreciated! Thank you in advance.

---

Extended coredumpctl of one i3 ID:

coredumpctl info 25822
           PID: 25822 (i3)
           UID: 1000 (alberto)
           GID: 1000 (alberto)
        Signal: 11 (SEGV)
     Timestamp: Thu 2025-01-30 21:13:33 CET (11min ago)
  Command Line: i3
    Executable: /usr/bin/i3
 Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/kitty-25001-0.scope
          Unit: user@1000.service
     User Unit: kitty-25001-0.scope
         Slice: user-1000.slice
     Owner UID: 1000 (alberto)
       Boot ID: d33fa1864459448ca75d0b238968a00d
    Machine ID: 40e45fecde5e4df48763cdccb4d072ed
      Hostname: archlinux
       Storage: /var/lib/systemd/coredump/core.i3.1000.d33fa1864459448ca75d0b238968a00d.25822.1738268013000000.zst (present)
  Size on Disk: 738.5K
       Message: Process 25822 (i3) of user 1000 dumped core.
                
                Stack trace of thread 25822:
                #0  0x00007ca2deee6e2f malloc (libc.so.6 + 0xa4e2f)
                #1  0x00007ca2deec0164 _IO_file_doallocate (libc.so.6 + 0x7e164)
                #2  0x00007ca2deecf594 _IO_doallocbuf (libc.so.6 + 0x8d594)
                #3  0x00007ca2deecd275 _IO_file_underflow (libc.so.6 + 0x8b275)
                #4  0x00007ca2deecf642 _IO_default_uflow (libc.so.6 + 0x8d642)
                #5  0x00007ca2deec1dcb _IO_getline_info (libc.so.6 + 0x7fdcb)
                #6  0x00007ca2deec0b06 _IO_fgets (libc.so.6 + 0x7eb06)
                #7  0x00007ca2df4bc589 n/a (libxcb-cursor.so.0 + 0x2589)
                #8  0x00007ca2df4bc82a n/a (libxcb-cursor.so.0 + 0x282a)
                #9  0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #10 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #11 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #12 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #13 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #14 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #15 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #16 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
...skipping...
                #38 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #39 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #40 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #41 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #42 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #43 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #44 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #45 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #46 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #47 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #48 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #49 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #50 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #51 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #52 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #53 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #54 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #55 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #56 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #57 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #58 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #59 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #60 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #61 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #62 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                #63 0x00007ca2df4bc975 n/a (libxcb-cursor.so.0 + 0x2975)
                
                Stack trace of thread 25828:
                #0  0x00007ca2def58ffd syscall (libc.so.6 + 0x116ffd)
                #1  0x00007ca2df0d2be0 g_cond_wait (libglib-2.0.so.0 + 0x8ebe0)
                #2  0x00007ca2df06998c n/a (libglib-2.0.so.0 + 0x2598c)
                #3  0x00007ca2df0699fd g_async_queue_pop (libglib-2.0.so.0 + 0x259fd)
                #4  0x00007ca2dea8279c n/a (libpangoft2-1.0.so.0 + 0xc79c)
                #5  0x00007ca2df0d6be6 n/a (libglib-2.0.so.0 + 0x92be6)
                #6  0x00007ca2deed62ce n/a (libc.so.6 + 0x942ce)
                #7  0x00007ca2def5b29c n/a (libc.so.6 + 0x11929c)
                ELF object binary architecture: AMD x86-64