Fix for Bug 21287.

Patch extracted and modified from attachment in Bug 21285.
The submitted patch was combining fix for 21285 and 21287.
It is extending the mutex protection in decrement_refcount() and remove_url().

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@102215 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/modules/experimental/mod_mem_cache.c b/modules/experimental/mod_mem_cache.c
index d717cc11a461c5916703eed9d097ea8719d6a32a..a5c9dec9212a9343c26db4315e13150fec16fb70 100644 (file)
--- a/modules/experimental/mod_mem_cache.c
+++ b/modules/experimental/mod_mem_cache.c
@@ -348,33 +348,26 @@ static apr_status_t decrement_refcount(void *arg)
             cache_remove(sconf->cache_cache, obj);
             obj->cleanup = 1;
         }
-        if (sconf->lock) {
-            apr_thread_mutex_unlock(sconf->lock);
-        }
+    }
+    else if (sconf->lock) {
+        apr_thread_mutex_lock(sconf->lock);
     }
 
     /* Cleanup the cache object */
 #ifdef USE_ATOMICS
-    if (!apr_atomic_dec32(&obj->refcount)) {
-        if (obj->cleanup) {
-            cleanup_cache_object(obj);
-        }
-    }
+    if (!apr_atomic_dec32(&obj->refcount) && (obj->cleanup)) {
 #else
-    if (sconf->lock) {
-        apr_thread_mutex_lock(sconf->lock);
-    }
     obj->refcount--;
     /* If the object is marked for cleanup and the refcount
      * has dropped to zero, cleanup the object
      */
     if ((obj->cleanup) && (!obj->refcount)) {
+#endif
         cleanup_cache_object(obj);
     }
     if (sconf->lock) {
         apr_thread_mutex_unlock(sconf->lock);
     }
-#endif
     return APR_SUCCESS;
 }
 static apr_status_t cleanup_cache_mem(void *sconfv)
@@ -739,35 +732,25 @@ static int remove_url(const char *type, const char *key)
   
     obj = cache_find(sconf->cache_cache, key);       
     if (obj) {
-        mem_cache_object_t *mobj;
         cache_remove(sconf->cache_cache, obj);
-        mobj = (mem_cache_object_t *) obj->vobj;
 
 #ifdef USE_ATOMICS
         /* Refcount increment in this case MUST be made under 
          * protection of the lock 
          */
         apr_atomic_inc32(&obj->refcount);
+        obj->cleanup = 1;
+        if (!apr_atomic_dec32(&obj->refcount)) {
 #else
+        obj->cleanup = 1;
         if (!obj->refcount) {
-            cleanup_cache_object(obj);
-            obj = NULL;
-        }
 #endif
-        if (obj) {
-            obj->cleanup = 1;
+            cleanup_cache_object(obj);
         }
     }
     if (sconf->lock) {
         apr_thread_mutex_unlock(sconf->lock);
     }
-#ifdef USE_ATOMICS
-    if (obj) {
-        if (!apr_atomic_dec32(&obj->refcount)) {
-            cleanup_cache_object(obj);
-        }
-    }
-#endif
     return OK;
 }