I attached valgrind log, may be you can find something usefull. >> #0 SYMBOL_NAME (sym=XIL(0x55555f9b3260)) at /usr/src/debug/emacs/emacs-29.4/src/lisp.h:1152 > Can you examine the memory it points to so we get a clue, maybe? > (gdb) x/64gx 0x55555f9b3200 So the idea is to use p-0x60, where where p from XIL(p)? Here new crash, and x/6gx: #0 SYMBOL_NAME (sym=0x555577a7a770) at /usr/src/debug/emacs/emacs-29.4/src/lisp.h:1152 1152 return p; (gdb) print sym $1 = (Lisp_Object) 0x555577a7a770 (gdb) xtype Lisp_Symbol (gdb) xsymbol $2 = (struct Lisp_Symbol *) 0xaaaacd8485d0 Cannot access memory at address 0xaaaacd8485d8 (gdb) x/64gx 0x555577a7a710 0x555577a7a710: 0x0000000000000004 0x0000555577a7a700 0x555577a7a720: 0x0000000000000004 0x0000555577a7a710 0x555577a7a730: 0x0000000000000004 0x0000555577a7a720 0x555577a7a740: 0x0000000000000004 0x0000555577a7a730 0x555577a7a750: 0x0000000000000004 0x0000555577a7a740 0x555577a7a760: 0x0000000000000004 0x0000555577a7a750 0x555577a7a770: 0x0000000000000004 0x0000555577a7a760 0x555577a7a780: 0x0000000000000004 0x0000555577a7a770 0x555577a7a790: 0x0000000000000004 0x0000555577a7a780 0x555577a7a7a0: 0x0000000000000004 0x0000555577a7a790 0x555577a7a7b0: 0x0000000000000004 0x0000555577a7a7a0 0x555577a7a7c0: 0x0000000000000004 0x0000555577a7a7b0 0x555577a7a7d0: 0x0000000000000004 0x0000555577a7a7c0 0x555577a7a7e0: 0x0000000000000000 0x0000555577a7a800 0x555577a7a7f0: 0x5f74736574225b3a 0x0000555577a77c00 0x555577a7a800: 0x0000555577a7a400 0x00005555810353d0 0x555577a7a810: 0x0000000000000004 0x0000555577a7a800 0x555577a7a820: 0x0000000000000004 0x0000555577a7a810 0x555577a7a830: 0x0000000000000004 0x0000555577a7a820 0x555577a7a840: 0x0000000000000004 0x0000555577a7a830 0x555577a7a850: 0x0000000000000004 0x0000555577a7a840 0x555577a7a860: 0x0000000000000004 0x0000555577a7a850 0x555577a7a870: 0x0000000000000004 0x0000555577a7a860 0x555577a7a880: 0x0000000000000004 0x0000555577a7a870 0x555577a7a890: 0x0000000000000004 0x0000555577a7a880 0x555577a7a8a0: 0x0000000000000004 0x0000555577a7a890 0x555577a7a8b0: 0x0000000000000004 0x0000555577a7a8a0 0x555577a7a8c0: 0x0000000000000004 0x0000555577a7a8b0 0x555577a7a8d0: 0x0000000000000004 0x0000555577a7a8c0 0x555577a7a8e0: 0x0000000000000004 0x0000555577a7a8d0 0x555577a7a8f0: 0x0000000000000004 0x0000555577a7a8e0 0x555577a7a900: 0x0000000000000004 0x0000555577a7a8f0 > If you can set a breakpoint on the function > "wrong_type_argument" (note there may be some false positives) "wrong_type_argument" for some reason triggers on every attempt to open file. I will try to rebuild emacs with sanitizer. -- /Evgeniy