[Tc2-checkins] [CSET 1.30] fix race in get_symbol

[<mr...@mr...>]

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2005/05/30 19:38:29+02:00 mr...@fo... =

#   fix race in get_symbol
# =

# kernel/module.c
#   2005/05/30 19:38:15+02:00 mr...@fo... +8 -4
#   proper locking around module loaded check in get_symbol
# =

diff -Nru a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c	2005-05-30 19:38:51 +02:00
+++ b/kernel/module.c	2005-05-30 19:38:51 +02:00
@@ -397,7 +397,7 @@
     tc2_module *module;
     tc2_symbol_t *sym;
 =

-    kprint("module", TC2_PRINT_DEBUG + 2, "%s: Getting symbol: %s\n",
+    kprint("get_symbol", TC2_PRINT_DEBUG + 2, "%s: Getting symbol: %s\n",
 	   cmod->module->name, csym);
  =

     if(tchash_find(avail_syms, csym, -1, &module) !=3D 0){
@@ -405,10 +405,14 @@
 	return NULL;
     }
 =

-    if(module->handle =3D=3D NULL){
-	_tc2_request(TC2_LOAD_MODULE, cmod, 1, interface, NULL);
+    pthread_mutex_lock(&module->mut);
+    if(!module->loaded){
+	_tc2_request(TC2_LOAD_MODULE, cmod, 0, interface, NULL);
+	while(!module->loaded)
+	    pthread_cond_wait(&module->cond, &module->mut);
 	module->autoclean =3D 1;
     }
+    pthread_mutex_unlock(&module->mut);
 =

     if(tchash_find(loaded_syms, csym, -1, &sym)){
 	kprint("module", TC2_PRINT_ERROR,
@@ -426,7 +430,7 @@
     if(cmod)
 	tc2_add_dep(cmod, module);
 =

-    kprint("module", TC2_PRINT_DEBUG + 2, "%s: Got symbol: %s -> %p\n",
+    kprint("get_symbol", TC2_PRINT_DEBUG + 2, "%s: Got symbol: %s -> %p\n",
 	   cmod->module->name, csym, sym->sym);
 =

     return sym;