https://gitlab.synchro.net/main/sbbs/-/issues/685#note_7998
Deuce, thanks for the reply. I have it working on x86_64 on Linux, but would love to get it working native Arm. I've tried on both MacOS and Linux with same seg fault result. I also looked at upgrading SpyderMonkey to a newer version, but the API has changed significantly and I think would unfortunately require quite a bit of re-wiring.
I've included a test Dockerfile (Debian 22) that reproduces it and captures the crash with LDD.
* Synchronet ARM64 SpiderMonkey 1.8.5 Debug Report
* Date: December 26, 2025
* Platform: Debian Bookworm (aarch64/ARM64)
* Build: Docker container, debian:bookworm-slim base
1. LDD Output
SpiderMonkey is statically linked into libsbbs.so, so no separate libmozjs*.so appears:
```
linux-vdso.so.1 (0x0000ffff85c02000)
libcap.so.2 => /lib/aarch64-linux-gnu/libcap.so.2
libsbbs.so => /sbbs/exec/libsbbs.so ← Contains static mozjs libftpsrvr.so => /sbbs/exec/libftpsrvr.so
libwebsrvr.so => /sbbs/exec/libwebsrvr.so
libmailsrvr.so => /sbbs/exec/libmailsrvr.so
libservices.so => /sbbs/exec/libservices.so
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6
/lib/ld-linux-aarch64.so.1
libnspr4.so => /lib/aarch64-linux-gnu/libnspr4.so
libarchive.so.13 => /lib/aarch64-linux-gnu/libarchive.so.13
libstdc++.so.6 => /lib/aarch64-linux-gnu/libstdc++.so.6
libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6
libgcc_s.so.1 => /lib/aarch64-linux-gnu/libgcc_s.so.1
libnettle.so.8 => /lib/aarch64-linux-gnu/libnettle.so.8
[... additional system libs ...]
```
Confirmation: No system mozjs packages installed. The static libmozjs185-1.0.a from the Synchronet 3rdp build is linked into libsbbs.so.
2. Build Configuration (from build.log)
SpiderMonkey configure flags:
```
./configure \
--with-system-nspr \
--disable-tests \
--disable-shared-js \ ← Static library
--enable-threadsafe \
--enable-ctypes \
--enable-optimize=-O3 \
--build=aarch64-linux-gnu \
--host=aarch64-linux-gnu \
--target=aarch64-linux-gnu
Final static library created:
libmozjs185-1.0.a
Linked into libsbbs.so:
g++ ... -o libsbbs.so ... /sbbs/src/sbbs3/../../3rdp/gcc.linux.aarch64.release/mozjs/lib/libmozjs185-1.0.a ...
```
3. Patches Applied (confirmed in build.log)
All patches were successfully applied during build:
```
patch -b -p0 -d .../mozjs/js-1.8.5 < js_src_jsnativestack_cpp.patch
patch -b -p0 -d .../mozjs < js-configure.patch
patch -b -p0 -d .../mozjs < js-configure.in.patch
patch -b -p0 -d .../mozjs < imacro-asm-fix.patch
patch -b -p0 -d .../mozjs < js-volatile-outside-functions.patch
patch -b -p0 -d .../mozjs < js-Wno-misleading-indentation.patch
patch -b -p0 -d .../mozjs < js-allow-python3.patch
patch -b -p0 -d .../mozjs < js-config.guess.patch
patch -b -p0 -d .../mozjs < js-makefile.patch
patch -b -p0 -d .../mozjs < js-disable-warnings.patch
patch -b -p0 -d .../mozjs < js-disable-shell.patch
patch -b -p0 -d .../mozjs < js-no-rwx-pages.patch
patch -b -p0 -d .../mozjs < js-darwin-configure.patch
patch -b -p0 -d .../mozjs < js-keep-ffi-cache.patch
patch -b -p0 -d .../mozjs < js-support-mingw-cross.patch
patch -b -p0 -d .../mozjs < js-int-main-conf.patch
patch -b -p0 -d .../mozjs < js-include-headers.patch
patch -b -p0 -d .../mozjs < js-macos-configure.patch
patch -b -p0 -d .../mozjs < js-isfinite.patch
patch -b -p0 -d .../mozjs < js-libffi-prefix.patch
patch -b -p0 -d .../mozjs < js-map-aligned.patch
```
No patch failures reported in the build output.
4. GDB Backtrace
```
Thread 12 "sbbs/events" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xffff70c0f180 (LWP 613)]
0x0000ffff7e70a250 in js_GetClassPrototype(JSContext*, JSObject*, JSProtoKey, JSObject**, js::Class*) ()
from /sbbs/exec/libsbbs.so
=== Backtrace ===
#0 0x0000ffff7e70a250 in js_GetClassPrototype(JSContext*, JSObject*, JSProtoKey, JSObject**, js::Class*) ()
from /sbbs/exec/libsbbs.so
#1 0x0000ffff7e6d45d4 in js_NewFunction(JSContext*, JSObject*, ...) ()
from /sbbs/exec/libsbbs.so
#2 0x0000ffff7e6d6e14 in js_DefineFunction(JSContext*, JSObject*, ...) ()
from /sbbs/exec/libsbbs.so
#3 0x0000ffff7e684d4c in JS_DefineFunctions ()
from /sbbs/exec/libsbbs.so
#4 0x0000ffff7e70c980 in js::DefineConstructorAndPrototype(JSContext*, JSObject*, JSProtoKey, ...) ()
from /sbbs/exec/libsbbs.so
#5 0x0000ffff7e70d5b0 in js_InitClass(JSContext*, JSObject*, ...) ()
from /sbbs/exec/libsbbs.so
#6 0x0000ffff7e6d4c5c in js_InitFunctionClass(JSContext*, JSObject*) ()
from /sbbs/exec/libsbbs.so
#7 0x0000ffff7e684b18 in js_InitFunctionAndObjectClasses(JSContext*, JSObject*) ()
from /sbbs/exec/libsbbs.so
#8 0x0000ffff7e684bb8 in JS_InitStandardClasses ()
from /sbbs/exec/libsbbs.so
#9 0x0000ffff7e58f710 in js_CreateGlobalObject ()
from /sbbs/exec/libsbbs.so
#10 0x0000ffff7e5e8884 in js_CreateCommonObjects ()
from /sbbs/exec/libsbbs.so
#11 0x0000ffff7e5e8bd4 in sbbs_t::js_init(JSRuntime**, JSObject**, char const*) ()
from /sbbs/exec/libsbbs.so
#12 0x0000ffff7e5f2988 in event_thread(void*) [clone .part.0] ()
from /sbbs/exec/libsbbs.so
#13 0x0000ffff7e1e2030 in start_thread (arg=0x0) at ./nptl/pthread_create.c:442 #14 0x0000ffff7e24bf1c in thread_start () at ../sysdeps/unix/sysv/linux/aarch64/clone.S:79
```
The crash occurs during JavaScript runtime initialization, specifically when js_InitFunctionClass() calls js_GetClassPrototype(). This happens in the "sbbs/events" thread before any user scripts run.
5. System Information
```
Architecture: aarch64 (ARM64)
OS: Debian GNU/Linux 12 (bookworm)
Kernel: Linux (Docker container)
Binary type: ELF 64-bit LSB pie executable, ARM aarch64
```
6. Memory Map (relevant sections)
```
0xffff7e400000 - 0xffff7ea23000 r-xp /sbbs/exec/libsbbs.so (6.1MB code) 0xffff7ea39000 - 0xffff7ea80000 r--p /sbbs/exec/libsbbs.so (data) 0xffff7ea80000 - 0xffff7eaa2000 rw-p /sbbs/exec/libsbbs.so (writable)
```
The crash address 0x0000ffff7e70a250 is within the executable code section of libsbbs.so.
7. Questions for Further Investigation
* Are there any ARM64/aarch64-specific patches that should be applied but aren't in the current patch set?
* Is there a known issue with js_GetClassPrototype() on ARM64 with this version of SpiderMonkey?
* The build uses `--with-system-nspr` — could there be an incompatibility between system NSPR (from Debian) and the SpiderMonkey build on ARM64?
* libffi is also built from source for ctypes support:
```
src/aarch64/ffi.o src/aarch64/sysv.o
```
Could there be an issue with the libffi ARM64 calling conventions?
Files Attached
* ldd-sbbs.txt - Full LDD output
* gdb-backtrace.txt - Complete GDB session with all thread backtraces
* build.log - Full build output (grep for "patch" to see patch application)
[build.log](/uploads/c280d8dd0279934a90058aa19f1e69a2/build.log)
[gdb-backtrace.txt](/uploads/8c30c259e1c19ac91cb918c434153284/gdb-backtrace.txt)
[ldd-sbbs.txt](/uploads/acaea3982a92d9ffd2ac2c9d0685c48c/ldd-sbbs.txt)
[Dockerfile.arm64-debug](/uploads/63f0746fc6530b075aa28bc336e0bfae/Dockerfile.arm64-debug)
---
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