ngx_mruby SIGSEGV with the latest mruby

gistfile1.txt

Program received signal SIGSEGV, Segmentation fault.
0x0000000000584ed5 in mrb_vm_exec (mrb=mrb@entry=0xbf3dd0, proc=<optimized out>, proc@entry=0xcb8680, pc=<optimized out>)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:1854
1854	      JUMP;
Missing separate debuginfos, use: debuginfo-install glibc-2.17-106.el7_2.6.x86_64 nss-softokn-freebl-3.16.2.3-13.el7_1.x86_64 openssl-libs-1.0.1e-51.el7_2.5.x86_64 pcre-8.32-15.el7_2.1.x86_64 zlib-1.2.7-15.el7.x86_64
(gdb) bt
#0  0x0000000000584ed5 in mrb_vm_exec (mrb=mrb@entry=0xbf3dd0, proc=<optimized out>, proc@entry=0xcb8680, pc=<optimized out>)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:1854
#1  0x000000000058af46 in mrb_vm_run (mrb=0xbf3dd0, proc=0xcb8680, self=..., stack_keep=<optimized out>)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:935
#2  0x000000000058ceee in mrb_run (mrb=<optimized out>, proc=<optimized out>, self=...)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:2985
#3  0x000000000054ec78 in ngx_mrb_run (r=0xde7720, state=0xbed168, code=0xcd9258, cached=1, result=0x0)
    at /home/vagrant/ngx_mruby/src/http/ngx_http_mruby_module.c:836
#4  0x00000000005512be in ngx_http_mruby_rewrite_inline_handler (r=0xde7720)
    at /home/vagrant/ngx_mruby/src/http/ngx_http_mruby_module.c:1575
#5  0x00000000004ae82e in ngx_http_core_rewrite_phase (r=0xde7720, ph=0xd63350) at src/http/ngx_http_core_module.c:905
#6  0x00000000004ae68b in ngx_http_core_run_phases (r=0xde7720) at src/http/ngx_http_core_module.c:851
#7  0x00000000004ae5f9 in ngx_http_handler (r=0xde7720) at src/http/ngx_http_core_module.c:834
#8  0x00000000004bd64a in ngx_http_process_request (r=0xde7720) at src/http/ngx_http_request.c:1948
#9  0x00000000004bbfd3 in ngx_http_process_request_headers (rev=0xbe0c10) at src/http/ngx_http_request.c:1375
#10 0x00000000004bb399 in ngx_http_process_request_line (rev=0xbe0c10) at src/http/ngx_http_request.c:1048
#11 0x00000000004b9f59 in ngx_http_wait_request_handler (rev=0xbe0c10) at src/http/ngx_http_request.c:506
#12 0x000000000049d5c7 in ngx_epoll_process_events (cycle=0xbdc530, timer=60000, flags=1)
    at src/event/modules/ngx_epoll_module.c:902
#13 0x000000000048c351 in ngx_process_events_and_timers (cycle=0xbdc530) at src/event/ngx_event.c:242
#14 0x0000000000499a89 in ngx_single_process_cycle (cycle=0xbdc530) at src/os/unix/ngx_process_cycle.c:309
#15 0x0000000000458040 in main (argc=1, argv=0x7fffffffe408) at src/core/nginx.c:378
(gdb) p pc
$1 = <optimized out>
(gdb) p *mrb->c
$2 = {prev = 0x0, stack = 0xc095c0, stbase = 0xc095c0, stend = 0xc09dc0, ci = 0xc09d80, cibase = 0xc09dd0, ciend = 0xc0a7d0, 
  rescue = 0x0, rsize = 0, ensure = 0x0, esize = 0, eidx = 0, status = MRB_FIBER_CREATED, vmexec = 0 '\000', fib = 0x0}
(gdb) p *mrb->c->ci
$3 = {mid = 0, proc = 0x0, stackent = 0x0, nregs = 0, ridx = 0, epos = 0, env = 0x0, pc = 0x0, err = 0x0, argc = 0, acc = 0, 
  target_class = 0xa11}
  
Fiberがらみだとすると、  https://github.com/mruby/mruby/issues/3789 ? 

その間に別のリクエストを受け取ると、別のスクリプトが実行される。

リダイレクト先の別のmrubyのハンドラーが動いているのかも。割り込んで実行されているのは以下のスクリプト。

irep 0xcea5b0 nregs=6 nlocals=1 pools=2 syms=7 reps=0
file: INLINE CODE
    1 000 OP_STRING	R1	L(0)	; "global_ngx_mruby"
    1 001 OP_GETCONST	R2	:Nginx
    1 002 OP_GETMCNST	R2	R2::Request
    1 003 OP_SEND	R2	:new	0
    1 004 OP_SEND	R2	:headers_out	0
    1 005 OP_STRING	R3	L(1)	; "Server"
    1 006 OP_MOVE	R4	R1	
    1 007 OP_SEND	R2	:[]=	2
    1 008 OP_GETCONST	R1	:Nginx
    1 009 OP_GETCONST	R2	:Nginx
    1 010 OP_GETMCNST	R2	R2::DECLINED
    1 011 OP_SEND	R1	:return	1
    1 012 OP_STOP

irep 0xcc3f80 nregs=6 nlocals=2 pools=5 syms=8 reps=0
file: INLINE CODE
    2 000 OP_GETCONST	R2	:Nginx
    2 001 OP_GETMCNST	R2	R2::Request	; 
    2 002 OP_SEND	R2	:new	0
    2 003 OP_MOVE	R1	R2		; R1:r
    3 004 OP_STRING	R2	L(0)	; "text/html"
    3 005 OP_MOVE	R3	R1		; R1:r
    3 006 OP_MOVE	R4	R2	
    3 007 OP_SEND	R3	:content_type=	1
    4 008 OP_GETCONST	R2	:Nginx
    4 009 OP_STRING	R3	L(1)	; "host => "
    4 010 OP_MOVE	R4	R1		; R1:r
    4 011 OP_SEND	R4	:var	0
    4 012 OP_SEND	R4	:host	0
    4 013 OP_STRCAT	R3	R4	
    4 014 OP_STRING	R4	L(2)	; " "
    4 015 OP_STRCAT	R3	R4	
    4 016 OP_SEND	R2	:rputs	1
    5 017 OP_GETCONST	R2	:Nginx
    5 018 OP_STRING	R3	L(3)	; "foo => "
    5 019 OP_MOVE	R4	R1		; R1:r
    5 020 OP_SEND	R4	:var	0
    5 021 OP_SEND	R4	:foo	0
    5 022 OP_STRCAT	R3	R4	
    5 023 OP_SEND	R2	:rputs	1
    5 024 OP_STOP

mruby/mruby@55431b4 で直ったっぽい。

mrb_codedump_all(mrb_state*, struct RProc*) 使うと irep のダンプが出来る。