luajit segmentation fault

[icodesource]

I am using the lua nginx module successfully with the standard lua interpreter. I tried it with luajit version 2.0 beta 5, but nginx crashes with a segmentation fault. What information can I provide to help resolve this issue? I'm running it on Snow Leopard Server. I'll try it with other versions of luajit to see if I can narrow down the problem. What versions of luajit have you tested with? Which platforms?

[chaoslawful]

Can you provide the version of nginx, and the stack backtrace when nginx crashed?
Does nginx crash with simplest lua code (i.e. ngx.echo(1))?

[chaoslawful]

And did all lua-nginx-module tests passed on your build?

[icodesource]

I tried it with 0.8.49 and 0.7.67. The test code is from you example:

    location /inline_concat {

        default_type 'text/plain';

        set $a "hello";
        set $b "world";

        set_by_lua $res "return ngx.arg[1]..ngx.arg[2]" $a $b;
        echo $res;
    }

The stack trace only had two entries:

#0 0x0000000100085e48 in lj_alloc_malloc ()
#1 0x00000001000660c7 in lj_state_newstate ()

I have done some fairly complicated with the non-jit version, including loading modules, so the non-jit version seems fine.

When I start nginx, it fails immediately with the segment fault, before I issue any requests are handled.

[agentzh]

I've tried nginx 0.7.67 and 0.8.49 with luajit 2.0 git HEAD (almost identical to the beta5 release kicked out these days), the whole tests suite is passing successfully on my x86_64 slackware linux :)

It may be an issue for LuaJIT 2.0's immature x86_64 support on Mac? I'll try to find a macbook to verify this. Thanks for reporting.

Cheers,
-agentzh

[icodesource]

Could be a mac thing. My production machines are linux, but I do all my development on the mac. If you need more information, let me know.

The module looks fantastic so far.

[chaoslawful]

I have someone tried nginx-0.8.49 and LuaJIT-2.0beta5 on a 32-bit Mac, and all tests passed. Could you run some Lua codes with your LuaJIT build? Does it work well when running as a standalone interpreter?

[icodesource]

Yes, I can run code on the standalone interpreter:

/usr/local/bin/luajit-2.0.0-beta5

[chaoslawful]

Could you download this example code and try it out on your Mac?
http://gist.github.com/551728

Download both con_run1.cc and con_run1.lua.

Compile and link con_run1.cc by:
$ g++ -I/usr/local/include/luajit-2.0 con_run1.cc -o con_run1 -L/usr/local/lib -lluajit-5.1

And run:
$ ./con_run1 con_run1.lua

Could you tell me if it crashes?

[icodesource]

Yes, it crashes. Stack trace is:

#0 0x000000010002b048 in lj_alloc_malloc ()
#1 0x000000010000b2c7 in lj_state_newstate ()

[chaoslawful]

OK...I've created a more minified example. Would you please try this again?
http://gist.github.com/553111

Compile and link min_con.c by:
$ gcc -I/usr/local/include/luajit-2.0 min_con.c -o min_con -L/usr/local/lib -lluajit-5.1

Run:
$ ./min_con

If this also crashes, I will submit a bug to LuaJIT.

[icodesource]

Yes, it crashed also. Backtrace is:

#0 0x000000010002b048 in lj_alloc_malloc ()
#1 0x0070006f0043003e in ?? ()

[chaoslawful]

It seems that LuaJIT requires some special linking options on 64-bit MacOS...Please try this cmdline and try min_con.c example again:

$ gcc -I/usr/local/include/luajit-2.0 min_con.c -o min_con -Wl,-pagezero_size,10000 -Wl,-image_base,100000000 -L/usr/local/lib -lluajit-5.1

[icodesource]

This works. I'll add these link options and try on nginx.

[chaoslawful]

Is lua-nginx-module working on your server after added these linking options?

[chaoslawful]

OK, consider it solved.