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Diffstat (limited to 'drivers/of/unittest.c')
-rw-r--r--drivers/of/unittest.c150
1 files changed, 148 insertions, 2 deletions
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index bc0f1e50a4be..b5a7a31d8bd2 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -54,8 +54,9 @@ static struct unittest_results {
* Print the expected message only if the current loglevel will allow
* the actual message to print.
*
- * Do not use EXPECT_BEGIN() or EXPECT_END() for messages generated by
- * pr_debug().
+ * Do not use EXPECT_BEGIN(), EXPECT_END(), EXPECT_NOT_BEGIN(), or
+ * EXPECT_NOT_END() to report messages expected to be reported or not
+ * reported by pr_debug().
*/
#define EXPECT_BEGIN(level, fmt, ...) \
printk(level pr_fmt("EXPECT \\ : ") fmt, ##__VA_ARGS__)
@@ -63,6 +64,12 @@ static struct unittest_results {
#define EXPECT_END(level, fmt, ...) \
printk(level pr_fmt("EXPECT / : ") fmt, ##__VA_ARGS__)
+#define EXPECT_NOT_BEGIN(level, fmt, ...) \
+ printk(level pr_fmt("EXPECT_NOT \\ : ") fmt, ##__VA_ARGS__)
+
+#define EXPECT_NOT_END(level, fmt, ...) \
+ printk(level pr_fmt("EXPECT_NOT / : ") fmt, ##__VA_ARGS__)
+
static void __init of_unittest_find_node_by_name(void)
{
struct device_node *np;
@@ -1488,6 +1495,7 @@ static int __init unittest_data_add(void)
struct device_node *next = np->sibling;
np->parent = of_root;
+ /* this will clear OF_DETACHED in np and children */
attach_node_and_children(np);
np = next;
}
@@ -2998,6 +3006,143 @@ out:
static inline void __init of_unittest_overlay(void) { }
#endif
+static void __init of_unittest_lifecycle(void)
+{
+#ifdef CONFIG_OF_DYNAMIC
+ unsigned int refcount;
+ int found_refcount_one = 0;
+ int put_count = 0;
+ struct device_node *np;
+ struct device_node *prev_sibling, *next_sibling;
+ const char *refcount_path = "/testcase-data/refcount-node";
+ const char *refcount_parent_path = "/testcase-data";
+
+ /*
+ * Node lifecycle tests, non-dynamic node:
+ *
+ * - Decrementing refcount to zero via of_node_put() should cause the
+ * attempt to free the node memory by of_node_release() to fail
+ * because the node is not a dynamic node.
+ *
+ * - Decrementing refcount past zero should result in additional
+ * errors reported.
+ */
+
+ np = of_find_node_by_path(refcount_path);
+ unittest(np, "find refcount_path \"%s\"\n", refcount_path);
+ if (np == NULL)
+ goto out_skip_tests;
+
+ while (!found_refcount_one) {
+
+ if (put_count++ > 10) {
+ unittest(0, "guardrail to avoid infinite loop\n");
+ goto out_skip_tests;
+ }
+
+ refcount = kref_read(&np->kobj.kref);
+ if (refcount == 1)
+ found_refcount_one = 1;
+ else
+ of_node_put(np);
+ }
+
+ EXPECT_BEGIN(KERN_INFO, "OF: ERROR: of_node_release() detected bad of_node_put() on /testcase-data/refcount-node");
+
+ /*
+ * refcount is now one, decrementing to zero will result in a call to
+ * of_node_release() to free the node's memory, which should result
+ * in an error
+ */
+ unittest(1, "/testcase-data/refcount-node is one");
+ of_node_put(np);
+
+ EXPECT_END(KERN_INFO, "OF: ERROR: of_node_release() detected bad of_node_put() on /testcase-data/refcount-node");
+
+
+ /*
+ * expect stack trace for subsequent of_node_put():
+ * __refcount_sub_and_test() calls:
+ * refcount_warn_saturate(r, REFCOUNT_SUB_UAF)
+ *
+ * Not capturing entire WARN_ONCE() trace with EXPECT_*(), just
+ * the first three lines, and the last line.
+ */
+ EXPECT_BEGIN(KERN_INFO, "------------[ cut here ]------------");
+ EXPECT_BEGIN(KERN_INFO, "WARNING: <<all>>");
+ EXPECT_BEGIN(KERN_INFO, "refcount_t: underflow; use-after-free.");
+ EXPECT_BEGIN(KERN_INFO, "---[ end trace <<int>> ]---");
+
+ /* refcount is now zero, this should fail */
+ unittest(1, "/testcase-data/refcount-node is zero");
+ of_node_put(np);
+
+ EXPECT_END(KERN_INFO, "---[ end trace <<int>> ]---");
+ EXPECT_END(KERN_INFO, "refcount_t: underflow; use-after-free.");
+ EXPECT_END(KERN_INFO, "WARNING: <<all>>");
+ EXPECT_END(KERN_INFO, "------------[ cut here ]------------");
+
+ /*
+ * Q. do we expect to get yet another warning?
+ * A. no, the WARNING is from WARN_ONCE()
+ */
+ EXPECT_NOT_BEGIN(KERN_INFO, "------------[ cut here ]------------");
+ EXPECT_NOT_BEGIN(KERN_INFO, "WARNING: <<all>>");
+ EXPECT_NOT_BEGIN(KERN_INFO, "refcount_t: underflow; use-after-free.");
+ EXPECT_NOT_BEGIN(KERN_INFO, "---[ end trace <<int>> ]---");
+
+ unittest(1, "/testcase-data/refcount-node is zero, second time");
+ of_node_put(np);
+
+ EXPECT_NOT_END(KERN_INFO, "---[ end trace <<int>> ]---");
+ EXPECT_NOT_END(KERN_INFO, "refcount_t: underflow; use-after-free.");
+ EXPECT_NOT_END(KERN_INFO, "WARNING: <<all>>");
+ EXPECT_NOT_END(KERN_INFO, "------------[ cut here ]------------");
+
+ /*
+ * refcount of zero will trigger stack traces from any further
+ * attempt to of_node_get() node "refcount-node". One example of
+ * this is where of_unittest_check_node_linkage() will recursively
+ * scan the tree, with 'for_each_child_of_node()' doing an
+ * of_node_get() of the children of a node.
+ *
+ * Prevent the stack trace by removing node "refcount-node" from
+ * its parent's child list.
+ *
+ * WARNING: EVIL, EVIL, EVIL:
+ *
+ * Directly manipulate the child list of node /testcase-data to
+ * remove child refcount-node. This is ignoring all proper methods
+ * of removing a child and will leak a small amount of memory.
+ */
+
+ np = of_find_node_by_path(refcount_parent_path);
+ unittest(np, "find refcount_parent_path \"%s\"\n", refcount_parent_path);
+ unittest(np, "ERROR: devicetree live tree left in a 'bad state' if test fail\n");
+ if (np == NULL)
+ return;
+
+ prev_sibling = np->child;
+ next_sibling = prev_sibling->sibling;
+ if (!strcmp(prev_sibling->full_name, "refcount-node")) {
+ np->child = next_sibling;
+ next_sibling = next_sibling->sibling;
+ }
+ while (next_sibling) {
+ if (!strcmp(next_sibling->full_name, "refcount-node"))
+ prev_sibling->sibling = next_sibling->sibling;
+ prev_sibling = next_sibling;
+ next_sibling = next_sibling->sibling;
+ }
+ of_node_put(np);
+
+ return;
+
+out_skip_tests:
+#endif
+ unittest(0, "One or more lifecycle tests skipped\n");
+}
+
#ifdef CONFIG_OF_OVERLAY
/*
@@ -3502,6 +3647,7 @@ static int __init of_unittest(void)
of_unittest_match_node();
of_unittest_platform_populate();
of_unittest_overlay();
+ of_unittest_lifecycle();
/* Double check linkage after removing testcase data */
of_unittest_check_tree_linkage();