lang/go coredumps on RPI4

[Ronald Klop]

On 4/29/21 5:03 PM, Ronald Klop wrote:
> Hi maintainer of lang/go and ports ML,
> 
> Latest go gives an Illegal Instruction on arm64.
> I'm running FreeBSD-14/arm64 on RPI4. Compilation of lang/go goes well. But follow-up ports like grafana7 and mongodb42-tools coredump during compilation.
> 
> [00:01:12] ===>  Building mongodump from ./mongodump/main
> [00:01:12] go tool compile: signal: illegal instruction (core dumped)
> [00:01:12] *** Error code 1
> [00:01:12]
> [00:01:12] Stop.
> [00:01:12] make: stopped in /usr/ports/databases/mongodb42-tools
> 
> I tried to get some debug info. I don't know if I got useful information here. I don't use gdb/lldb and go that often.
> 
> root at rpi4:/ # /usr/bin/lldb -c var/tmp/65534.compile.0.63376.core /usr/local/go/pkg/tool/freebsd_arm64/compile
> (lldb) target create "/usr/local/go/pkg/tool/freebsd_arm64/compile" --core "var/tmp/65534.compile.0.63376.core"
> Core file '/var/tmp/65534.compile.0.63376.core' (aarch64) was loaded.
> 
> Cannot read termcap database;
> using dumb terminal settings.
> (lldb) bt
> This version of LLDB has no plugin for the go language. Inspection of frame variables will be limited.
> * thread #1, name = 'compile', stop reason = signal SIGILL
>    * frame #0: 0x0000000000074880 compile`_rt0_arm64_freebsd at rt0_freebsd_arm64.s:9
>      frame #1: 0x0000000000074880 compile`runtime.asyncPreempt at preempt_arm64.s:148
> (lldb) quit
> 
> 
> NB: This compiles fine on the FreeBSD pkg builders. So it might have something todo with ARMv8.1 vs ARMv8.2 instruction set. I'm not familiar with this.
> NB2: It also compiles fine in a FreeBSD-12 jail which uses an older clang version.
> 
> Regards,
> 
> Ronald.
> 
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Gdb gives about the same output and I learned the "disass" command.
UDF instruction seems to be UNDefined so it might get into a codepath which it should not get into.


[root at rpi4 /var/tmp]# gdb /usr/local/go/pkg/tool/freebsd_arm64/compile ./0.compile.0.84815.core
GNU gdb (GDB) 10.1 [GDB v10.1 for FreeBSD]
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Type "show configuration" for configuration details.
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Reading symbols from /usr/local/go/pkg/tool/freebsd_arm64/compile...
[New LWP 298311]
Core was generated by `/usr/local/go/pkg/tool/freebsd_arm64/compile -V=full'.
Program terminated with signal SIGILL, Illegal instruction.
#0  _rt0_arm64_freebsd () at /usr/local/go/src/runtime/rt0_freebsd_arm64.s:9
9		ADD	$8, R0, R1	// argv
warning: File "/usr/local/go/src/runtime/runtime-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
	add-auto-load-safe-path /usr/local/go/src/runtime/runtime-gdb.py
line to your configuration file "/root/.gdbinit".
--Type <RET> for more, q to quit, c to continue without paging--
To completely disable this security protection add
	set auto-load safe-path /
line to your configuration file "/root/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
	info "(gdb)Auto-loading safe path"
(gdb) bt
#0  _rt0_arm64_freebsd () at /usr/local/go/src/runtime/rt0_freebsd_arm64.s:9
(gdb) disass
Dump of assembler code for function _rt0_arm64_freebsd:
=> 0x0000000000074880 <+0>:	udf	#0
    0x0000000000074884 <+4>:	udf	#0
    0x0000000000074888 <+8>:	udf	#0
    0x000000000007488c <+12>:	udf	#0
End of assembler dump.


I can reproduce it by running a simple "go run helloworld.go".

Any thoughts?

Regards,
Ronald.