Comment 2 for bug 1918855

After two times pass for using mesa lib in ppa:oibaf/graphics-drivers, I reproduce the x server stop error with different stacktrace:

Mar 12 12:43:12 stress-ng: memory (MB): total 15729.63, free 152.17, shared 43.86, buffer 0.36, swap 2048.00, free swap 0.01
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE)
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) Backtrace:
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 0: /usr/lib/xorg/Xorg (OsLookupColor+0x13c) [0x55d66e90159c]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 1: /lib/x86_64-linux-gnu/libpthread.so.0 (funlockfile+0x60) [0x7f5f95cc941f]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (gsignal+0xcb) [0x7f5f95b0618b]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 3: /lib/x86_64-linux-gnu/libc.so.6 (abort+0x12b) [0x7f5f95ae5859]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) unw_get_proc_name failed: no unwind info found [-10]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 4: /usr/lib/x86_64-linux-gnu/dri/iris_dri.so (?+0x0) [0x7f5f939fd665]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 5: /usr/lib/x86_64-linux-gnu/dri/iris_dri.so (nouveau_drm_screen_create+0x29a098) [0x7f5f948c5d08]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 6: /usr/lib/x86_64-linux-gnu/dri/iris_dri.so (__driDriverGetExtensions_zink+0x7cf0d) [0x7f5f93b0214d]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 7: /usr/lib/xorg/Xorg (present_register_complete_notify+0x673) [0x55d66e87dcf3]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 8: /usr/lib/xorg/Xorg (present_register_complete_notify+0x1fd9) [0x55d66e880ee9]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 9: /usr/lib/xorg/Xorg (present_register_complete_notify+0x809) [0x55d66e87e069]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 10: /usr/lib/xorg/Xorg (present_register_complete_notify+0x845) [0x55d66e87e105]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 11: /usr/lib/xorg/Xorg (TimerSet+0x180) [0x55d66e8fabd0]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 12: /usr/lib/xorg/Xorg (TimerSet+0x1e8) [0x55d66e8fac88]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 13: /usr/lib/xorg/Xorg (WaitForSomething+0x235) [0x55d66e8fad25]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 14: /usr/lib/xorg/Xorg (SendErrorToClient+0x117) [0x55d66e79fcf7]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 15: /usr/lib/xorg/Xorg (InitFonts+0x3b4) [0x55d66e7a3fc4]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 16: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xf3) [0x7f5f95ae70b3]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) 17: /usr/lib/xorg/Xorg (_start+0x2e) [0x55d66e78da2e]
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE)
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE)
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: Fatal server error:
Mar 12 12:43:12 /usr/lib/gdm3/gdm-x-session[1949]: (EE) Caught signal 6 (Aborted). Server aborting

The detail log is in lp:1917692.