Re: thread assert with 1.8.2

[Ludovic Courtès]

Hi,

Greg Troxel <address@hidden> writes:

> Running threads.test
> guile: Error detected by libpthread: Unlocking unlocked mutex.
> Detected by file 
> "/usr/home/gdt/NetBSD-current/src/lib/libpthread/pthread_mutex.c", line 357, 
> function "pthread_mutex_unlock".
> See pthread(3) for information.
> [1]   Abort trap (core dumped) ${dir}${tst}
>
> The core has several threads, nad this is the one that hit the assert:
>
> (gdb) bt
> #0  0xbb9d6bdb in kill () from /usr/lib/libc.so.12
> #1  0xbbaa3d9b in pthread__errorfunc () from /usr/lib/libpthread.so.0
> #2  0xbbaa1d49 in pthread_mutex_unlock () from /usr/lib/libpthread.so.0
> #3  0xbbb9875c in scm_leave_guile () from 
> /usr/home/gdt/NetBSD-current/pkgsrc/lang/guile/work/guile-1.8.2/libguile/.libs/libguile.so.17
> #4  0xbbb99c4e in on_thread_exit () from 
> /usr/home/gdt/NetBSD-current/pkgsrc/lang/guile/work/guile-1.8.2/libguile/.libs/libguile.so.17
> #5  0xbbaa0e1c in pthread__destroy_tsd () from /usr/lib/libpthread.so.0
> #6  0xbbaa5119 in pthread_exit () from /usr/lib/libpthread.so.0
> #7  0xbbaa5499 in pthread_setcancelstate () from /usr/lib/libpthread.so.0
> #8  0xbb9f9370 in swapcontext () from /usr/lib/libc.so.12

I fixed this one (thank you Greg!) and it turned out to be easier than I
expected: threads were leaving guile mode twice, once in
`scm_i_with_guile_and_parent ()' and then once in `on_thread_exit ()',
hence the above assertion failure.

But now, there's a similar issue in HEAD with `(ice-9 i18n)':

  PASS: locale objects: make-locale (2 args)
  PASS: locale objects: make-locale (2 args, list)
  PASS: locale objects: make-locale (3 args)
  guile: Error detected by libpthread: Unlocking unlocked mutex.
  Detected by file "/n0/gdt/NetBSD-4/src/lib/libpthread/pthread_mutex.c", line 
363, function "pthread_mutex_unlock".

Backtrace:

  #0  0xbba68fff in kill () from /usr/lib/libc.so.12
  #1  0xbb9dadb3 in pthread__errorfunc () from /usr/lib/libpthread.so.0
  #2  0xbb9d93f8 in pthread_mutex_unlock () from /usr/lib/libpthread.so.0
  #3  0xbb9cbaa0 in scm_make_locale (category_list=0x2, locale_name=0x80d6870, 
base_locale=0x204) at ../../libguile/i18n.c:436

Needs further investigation...

Thanks,
Ludovic.

--- orig/ChangeLog
+++ mod/ChangeLog
@@ -1,6 +1,6 @@
 2007-10-02  Ludovic Courtès  <address@hidden>
 
-       * NEWS: Mention `(ice-9 slib)' fix.
+       * NEWS: Mention `(ice-9 slib)' fix and threading fix.
 
 2007-09-03  Ludovic Courtès  <address@hidden>
 


--- orig/NEWS
+++ mod/NEWS
@@ -46,6 +46,7 @@
 ** Warnings about duplicate bindings now go to stderr
 ** A memory leak in `make-socket-address' was fixed
 ** Alignment issues (e.g., on SPARC) in network routines were fixed
+** A threading issue that showed up at least on NetBSD was fixed
 ** Build problems on Solaris fixed
 
 * Implementation improvements


--- orig/libguile/ChangeLog
+++ mod/libguile/ChangeLog
@@ -1,3 +1,9 @@
+2007-10-02  Ludovic Courtès  <address@hidden>
+
+       * threads.c (on_thread_exit): Don't call `scm_leave_guile ()'
+       since we're already in non-guile mode.  Reported by Greg Toxel
+       for NetBSD.
+
 2007-10-01  Ludovic Courtès  <address@hidden>
 
        * ports.c (flush_output_port): Expect directly a port instead of


--- orig/libguile/threads.c
+++ mod/libguile/threads.c
@@ -495,20 +495,18 @@
 static void
 on_thread_exit (void *v)
 {
+  /* This handler is executed in non-guile mode.  */
   scm_i_thread *t = (scm_i_thread *)v, **tp;
 
   scm_i_pthread_setspecific (scm_i_thread_key, v);
 
   /* Unblocking the joining threads needs to happen in guile mode
-     since the queue is a SCM data structure.
-  */
+     since the queue is a SCM data structure.  */
   scm_with_guile (do_thread_exit, v);
 
   /* Removing ourself from the list of all threads needs to happen in
      non-guile mode since all SCM values on our stack become
-     unprotected once we are no longer in the list.
-  */
-  scm_leave_guile ();
+     unprotected once we are no longer in the list.  */
   scm_i_pthread_mutex_lock (&thread_admin_mutex);
   for (tp = &all_threads; *tp; tp = &(*tp)->next_thread)
     if (*tp == t)