SIGSEGV on 32bit linux

[yyamano]

I got SIGSEGV on 32bit linux when run ngx_mruby/test/t/ngx_mruby.rb

RuntimeError: ngx_mruby - stream tcp load balancer [127.0.0.1:12346 to 127.0.0.1:58081 which changed from 127.0.0.1:58080 by mrub\
y] => sysread failed
Total: 70
   OK: 69
   KO: 0
Crash: 1
 Time: 1.181836 seconds

trace:
        [0] /home/vagrant/ngx_mruby/mruby_test/build/mrbgems/mruby-simpletest/mrblib/mrb_simpletest.rb:240:in SimpleTest.report
        [1] ../test/t/ngx_mruby.rb:538
/home/vagrant/ngx_mruby/mruby_test/build/mrbgems/mruby-simpletest/mrblib/mrb_simpletest.rb:240: RuntimeError

Here is the gdb backtrace:

vagrant@vagrant-ubuntu-trusty-32:~$ curl http://localhost:12346/mruby

Program received signal SIGSEGV, Segmentation fault.
0x08174c07 in ngx_stream_mrb_errlogger (mrb=0x862cb10, self=...) at /home/vagrant/ngx_mruby/src/stream/ngx_stream_mruby_core.c:57
57	  ngx_log_error((ngx_uint_t)log_level, s->connection->log, 0, "%s", mrb_str_to_cstr(mrb, msg));
(gdb) bt
#0  0x08174c07 in ngx_stream_mrb_errlogger (mrb=0x862cb10, self=...)
    at /home/vagrant/ngx_mruby/src/stream/ngx_stream_mruby_core.c:57
#1  0x0818e1ac in mrb_vm_exec (mrb=mrb@entry=0x862cb10, proc=<optimized out>, proc@entry=0x865a058, pc=0x8694818)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:1150
#2  0x08193d8f in mrb_vm_run (stack_keep=2, self=..., proc=0x865a058, mrb=0x862cb10)
    at /home/vagrant/ngx_mruby/mruby/src/vm.c:759
#3  mrb_run (mrb=0x862cb10, proc=0x865a058, self=...) at /home/vagrant/ngx_mruby/mruby/src/vm.c:2424
#4  0x08174807 in ngx_stream_mruby_handler (s=0x8561870) at /home/vagrant/ngx_mruby/src/stream/ngx_stream_mruby_module.c:681
#5  0x081519fd in ngx_stream_core_generic_phase (s=0x8561870, ph=0x868578c) at src/stream/ngx_stream_core_module.c:176
#6  0x08151977 in ngx_stream_core_run_phases (s=0x8561870) at src/stream/ngx_stream_core_module.c:153
#7  0x08151485 in ngx_stream_session_handler (rev=0x86886a8) at src/stream/ngx_stream_handler.c:292
#8  0x08151123 in ngx_stream_init_connection (c=0x868b088) at src/stream/ngx_stream_handler.c:201
#9  0x080bff63 in ngx_event_accept (ev=0x8688618) at src/event/ngx_event_accept.c:309
#10 0x080cc857 in ngx_epoll_process_events (cycle=0x85623e8, timer=4294967295, flags=1)
    at src/event/modules/ngx_epoll_module.c:907
#11 0x080bd0f1 in ngx_process_events_and_timers (cycle=0x85623e8) at src/event/ngx_event.c:242
#12 0x080c9434 in ngx_single_process_cycle (cycle=0x85623e8) at src/os/unix/ngx_process_cycle.c:309
#13 0x080902e3 in main (argc=1, argv=0xbffff744) at src/core/nginx.c:364

I guess the root cause is same as #229. Will fix it as a lunch time hack:-)

Breakpoint 2, ngx_stream_mruby_handler (s=0x8561870) at /home/vagrant/ngx_mruby/src/stream/ngx_stream_mruby_module.c:674
674	  ngx_stream_mruby_srv_conf_t *mscf = ngx_stream_get_module_srv_conf(s, ngx_stream_mruby_module);
(gdb) p s->connection
$10 = (ngx_connection_t *) 0x868b088
(gdb) p *(s->connection)
$11 = {data = 0x8561870, read = 0x86886a8, write = 0x85e1c20, fd = 18, recv = 0x80c4d6f <ngx_unix_recv>, 
  send = 0x80c5583 <ngx_unix_send>, recv_chain = 0x80c4fde <ngx_readv_chain>, send_chain = 0x80cca72 <ngx_linux_sendfile_chain>, 
  listening = 0x8685c80, sent = 0, log = 0x8561838, pool = 0x8561800, type = 1, sockaddr = 0x8561828, socklen = 16, addr_text = {
    len = 9, data = 0x8561860 "127.0.0.1"}, proxy_protocol_addr = {len = 0, data = 0x0}, proxy_protocol_port = 0, ssl = 0x0, 
  local_sockaddr = 0x86857a8, local_socklen = 16, buffer = 0x0, queue = {prev = 0x0, next = 0x0}, number = 1, requests = 0, 
  buffered = 0, log_error = 2, timedout = 0, error = 0, destroyed = 0, idle = 0, reusable = 0, close = 0, shared = 0, 
  sendfile = 0, sndlowat = 0, tcp_nodelay = 0, tcp_nopush = 0, need_last_buf = 0}
(gdb) p sizeof(*(s->connection))
$12 = 120

Breakpoint 1, ngx_stream_mrb_errlogger (mrb=0x862cb10, self=...) at /home/vagrant/ngx_mruby/src/stream/ngx_stream_mruby_core.c:30
30	  ngx_stream_mruby_internal_ctx_t *ictx = mrb->ud;
(gdb) n
31	  ngx_stream_session_t *s = ictx->s;
(gdb) n
33	  if (s == NULL) {
(gdb) p s->connection
$13 = (ngx_connection_t *) 0x868b088
(gdb) p *(s->connection)
$14 = {data = 0x8561870, read = 0x86886a8, write = 0x85e1c20, fd = 18, recv = 0x80c4d6f <ngx_unix_recv>, 
  send = 0x80c5583 <ngx_unix_send>, recv_chain = 0x80c4fde <ngx_readv_chain>, send_chain = 0x80cca72 <ngx_linux_sendfile_chain>, 
  listening = 0x8685c80, sent = 0, log = 0x0, pool = 0x8561838, type = 139859968, sockaddr = 0x1, socklen = 139860008, 
  addr_text = {len = 16, data = 0x9 <error: Cannot access memory at address 0x9>}, proxy_protocol_addr = {len = 139860064, 
    data = 0x0}, proxy_protocol_port = 0, ssl = 0x0, local_sockaddr = 0x0, local_socklen = 141055912, buffer = 0x10, queue = {
    prev = 0x0, next = 0x0}, number = 0, requests = 1, buffered = 0, log_error = 0, timedout = 0, error = 0, destroyed = 0, 
  idle = 0, reusable = 0, close = 0, shared = 0, sendfile = 0, sndlowat = 0, tcp_nodelay = 0, tcp_nopush = 0, need_last_buf = 0}
(gdb) p sizeof(*(s->connection))
$15 = 116