After the last x.org-crash with kernel 5.12 I looked into ~/.local/share/xorg/Xorg.0.log and found the following
[ 258.184] (EE) 0: /usr/lib/Xorg (xorg_backtrace+0x53) [0x555a35ecafd3]
[ 258.184] (EE) 1: /usr/lib/Xorg (0x555a35d84000+0x151df5) [0x555a35ed5df5]
[ 258.184] (EE) 2: /usr/lib/libc.so.6 (0x7f2536651000+0x3cf80) [0x7f253668df80]
[ 258.184] (EE) 3: /usr/lib/Xorg (0x555a35d84000+0xc1fde) [0x555a35e45fde]
[ 258.184] (EE) 4: /usr/lib/Xorg (0x555a35d84000+0x1b9611) [0x555a35f3d611]
[ 258.184] (EE) 5: /usr/lib/Xorg (0x555a35d84000+0xd2a72) [0x555a35e56a72]
[ 258.184] (EE) 6: /usr/lib/Xorg (0x555a35d84000+0xd9241) [0x555a35e5d241]
[ 258.184] (EE) 7: /usr/lib/Xorg (0x555a35d84000+0xdabac) [0x555a35e5ebac]
[ 258.184] (EE) 8: /usr/lib/Xorg (0x555a35d84000+0xd72ec) [0x555a35e5b2ec]
[ 258.184] (EE) 9: /usr/lib/Xorg (0x555a35d84000+0x3a195) [0x555a35dbe195]
[ 258.184] (EE) 10: /usr/lib/libc.so.6 (__libc_start_main+0xd5) [0x7f2536678b25]
[ 258.184] (EE) 11: /usr/lib/Xorg (_start+0x2e) [0x555a35dbe5de]
[ 258.184] (EE)
[ 258.184] (EE) Segmentation fault at address 0x20
[ 258.184] (EE)
Fatal server error:
[ 258.184] (EE) Caught signal 11 (Segmentation fault). Server aborting
Is this of some help?