[Gauche-devel] segfault with threads

[<mm...@ma...>]

Hello Shiro and all, 

I have a kahua application, which segfaults iff I use threads.
The program uses custom C bindings, so I don't claim it's not a
bug in my code.  But the fault occurs always at the same
point (in gauche code), so maybe some hint would help me.


The fault is this:

[Switching to Thread -1212094784 (LWP 1321)]
0xb7df43b0 in run_loop () at vm.c:1126
1126                CASE(SCM_VM_LREF20) { VAL0 = ENV_DATA(ENV->up->up, 0);NEXT1; }
(gdb) bt
#0  0xb7df43b0 in run_loop () at vm.c:1126
#1  0xb7dfc698 in user_eval_inner (program=0x8c24580, codevec=0x80ead48) at vm.c:2919
#2  0x0804a3d1 in main (argc=11, argv=0xbf960a64) at main.c:425


The program uses 2 helper threads only at one point.
To trace down the problem I tried to run those threads serially.

Here is how I make the threads run serially:

(let1 t1 (load-people-list pg "f")
  (if (thread? t1)
      (thread-join! t1)))
(let1 t2 (load-people-list pg "m")
  (if (thread? t2)
      (thread-join! t2)))


And this is the worker, where I can switch off use of threads:

(define (load-people-list pg gender)
  (let1 pgh (pg:new-handle pg :private #t)
    
    (logformat-color 'yellow "pg:new-handle: backend ~d\n"
      (pg-backend-pid (ref pgh 'conn)))

    (if (and (eq? 'pthread (gauche-thread-type))
             #f) ;; <--- Now I don't want threads
        (let1 t (make-thread
                 (lambda ()
                   (logformat-color 'yellow "Thread started!\n")

                   (do-load pgh gender)
                   (pg:dispose-handle pg pgh)

                   (logformat-color 'yellow "Thread exiting!\n"))
                 "loader thread")
          (thread-start! t)
          t)
      (begin
        (do-load pgh gender)
        (pg:dispose-handle pg pgh)
        #t
        ))))


So, If I enable threads, programs segfaults always at the same point,
If I disable them, all is ok.


thanks.


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