Backport 552161 from trunk:

Avoid overwriting the hash_mutex table for applications that incorrectly calls
apr_atomic_init().

Noticied by: Tim Jones
PR: 42760


git-svn-id: http://svn.apache.org/repos/asf/apr/apr/branches/1.2.x@552163 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 19 insertions, 0 deletions

diff --git a/CHANGES b/CHANGES
index 493b20bbe..730471e80 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,8 @@
 Changes for APR 1.2.10
 
+  *) Avoid overwriting the hash_mutex table for applications that
+     incorrectly calls apr_atomic_init().  PR 42760.  [Davi Arnaut]
+
   *) Allow IPv6 connectivity test to fail, avoiding a potentially fatal
      error.  [Davi Arnaut]
 
diff --git a/atomic/unix/apr_atomic.c b/atomic/unix/apr_atomic.c
index 3110d96d7..ed85a429b 100644
--- a/atomic/unix/apr_atomic.c
+++ b/atomic/unix/apr_atomic.c
@@ -171,12 +171,28 @@ APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem,
 static apr_thread_mutex_t **hash_mutex;
 #endif /* APR_HAS_THREADS */
 
+#if APR_HAS_THREADS
+static apr_status_t atomic_cleanup(void *data)
+{
+    if (hash_mutex == data)
+        hash_mutex = NULL;
+
+    return APR_SUCCESS;
+}
+#endif
+
 apr_status_t apr_atomic_init(apr_pool_t *p)
 {
 #if APR_HAS_THREADS
     int i;
     apr_status_t rv;
+
+    if (hash_mutex != NULL)
+        return APR_SUCCESS;
+
     hash_mutex = apr_palloc(p, sizeof(apr_thread_mutex_t*) * NUM_ATOMIC_HASH);
+    apr_pool_cleanup_register(p, hash_mutex, atomic_cleanup,
+                              apr_pool_cleanup_null);
 
     for (i = 0; i < NUM_ATOMIC_HASH; i++) {
         rv = apr_thread_mutex_create(&(hash_mutex[i]),