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authorAndrew Tridgell <tridge@samba.org>2006-05-23 03:51:44 +0000
committerGerald (Jerry) Carter <jerry@samba.org>2007-10-10 14:08:28 -0500
commit5da75f5c3631247615efdf73fae2481df6908cb8 (patch)
tree4eb12992cb255312ef70f0d8dafee7f65a8e9328 /source4/lib/talloc
parent495652fe24da009bdef839be9eb543837ecaab04 (diff)
downloadsamba-5da75f5c3631247615efdf73fae2481df6908cb8.tar.gz
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r15824: fixed a subtle talloc bug to do with memory context loops. When you
have a structure that references one of its parents, and a parent of that parent is freed, then the whole structure should be freed, not just the reference. this was found by the change notify code, as a side effect of fixing the memory leak yesterday (This used to be commit 70531dcaeeb9314d410baa0d285df6a265311541)
Diffstat (limited to 'source4/lib/talloc')
-rw-r--r--source4/lib/talloc/talloc.c36
-rw-r--r--source4/lib/talloc/talloc.h1
-rw-r--r--source4/lib/talloc/testsuite.c46
3 files changed, 80 insertions, 3 deletions
diff --git a/source4/lib/talloc/talloc.c b/source4/lib/talloc/talloc.c
index 8f046a02b8..823ae4ffb3 100644
--- a/source4/lib/talloc/talloc.c
+++ b/source4/lib/talloc/talloc.c
@@ -542,7 +542,13 @@ int talloc_free(void *ptr)
tc = talloc_chunk_from_ptr(ptr);
if (tc->refs) {
+ int is_child;
+ struct talloc_reference_handle *handle = tc->refs;
+ is_child = talloc_is_parent(handle, handle->ptr);
talloc_reference_destructor(tc->refs);
+ if (is_child) {
+ return talloc_free(ptr);
+ }
return -1;
}
@@ -1197,7 +1203,9 @@ void *talloc_find_parent_byname(const void *context, const char *name)
return TC_PTR_FROM_CHUNK(tc);
}
while (tc && tc->prev) tc = tc->prev;
- tc = tc->parent;
+ if (tc) {
+ tc = tc->parent;
+ }
}
return NULL;
}
@@ -1219,6 +1227,30 @@ void talloc_show_parents(const void *context, FILE *file)
while (tc) {
fprintf(file, "\t'%s'\n", talloc_get_name(TC_PTR_FROM_CHUNK(tc)));
while (tc && tc->prev) tc = tc->prev;
- tc = tc->parent;
+ if (tc) {
+ tc = tc->parent;
+ }
+ }
+}
+
+/*
+ return 1 if ptr is a parent of context
+*/
+int talloc_is_parent(const void *context, const char *ptr)
+{
+ struct talloc_chunk *tc;
+
+ if (context == NULL) {
+ return 0;
+ }
+
+ tc = talloc_chunk_from_ptr(context);
+ while (tc) {
+ if (TC_PTR_FROM_CHUNK(tc) == ptr) return 1;
+ while (tc && tc->prev) tc = tc->prev;
+ if (tc) {
+ tc = tc->parent;
+ }
}
+ return 0;
}
diff --git a/source4/lib/talloc/talloc.h b/source4/lib/talloc/talloc.h
index 68bf24e0b8..99410241a6 100644
--- a/source4/lib/talloc/talloc.h
+++ b/source4/lib/talloc/talloc.h
@@ -137,6 +137,7 @@ void *talloc_autofree_context(void);
size_t talloc_get_size(const void *ctx);
void *talloc_find_parent_byname(const void *ctx, const char *name);
void talloc_show_parents(const void *context, FILE *file);
+int talloc_is_parent(const void *context, const char *ptr);
#endif
diff --git a/source4/lib/talloc/testsuite.c b/source4/lib/talloc/testsuite.c
index b03be98587..018d734cc3 100644
--- a/source4/lib/talloc/testsuite.c
+++ b/source4/lib/talloc/testsuite.c
@@ -824,7 +824,7 @@ static BOOL test_speed(void)
}
-BOOL test_lifeless(void)
+static BOOL test_lifeless(void)
{
char *top = talloc_new(NULL);
char *parent, *child;
@@ -836,10 +836,53 @@ BOOL test_lifeless(void)
child = talloc_strdup(parent, "child");
talloc_reference(child, parent);
talloc_reference(child_owner, child);
+ talloc_report_full(top, stdout);
talloc_unlink(top, parent);
talloc_free(child);
talloc_report_full(top, stdout);
talloc_free(top);
+ talloc_free(child_owner);
+#if 0
+ talloc_free(child);
+#endif
+ return True;
+}
+
+static int loop_destructor_count;
+
+static int test_loop_destructor(void *ptr)
+{
+ printf("loop destructor\n");
+ loop_destructor_count++;
+ return 0;
+}
+
+static BOOL test_loop(void)
+{
+ char *top = talloc_new(NULL);
+ char *parent;
+ struct req1 {
+ char *req2, *req3;
+ } *req1;
+
+ printf("TESTING TALLOC LOOP DESTRUCTION\n");
+ parent = talloc_strdup(top, "parent");
+ req1 = talloc(parent, struct req1);
+ req1->req2 = talloc_strdup(req1, "req2");
+ talloc_set_destructor(req1->req2, test_loop_destructor);
+ req1->req3 = talloc_strdup(req1, "req3");
+ talloc_reference(req1->req3, req1);
+ talloc_report_full(top, stdout);
+ talloc_free(parent);
+ talloc_report_full(top, stdout);
+ talloc_report_full(NULL, stdout);
+ talloc_free(top);
+
+ if (loop_destructor_count != 1) {
+ printf("FAILED TO FIRE LOOP DESTRUCTOR\n");
+ return False;
+ }
+
return True;
}
@@ -861,6 +904,7 @@ BOOL torture_local_talloc(struct torture_context *torture)
ret &= test_realloc_fn();
ret &= test_type();
ret &= test_lifeless();
+ ret &= test_loop();
if (ret) {
ret &= test_speed();
}