On 10/14/18 18:06, Joe Perches wrote:

On Sun, 2018-10-14 at 17:24 -0700, frowand.list@gmail.com wrote:

quoted

From: Frank Rowand <redacted>

Add test case of two fragments updating the same property.  After
adding the test case, the system hangs at end of boot, after
after slub stack dumps from kfree() in crypto modprobe code.

[]

quoted

-static int check_changeset_dup_add_node(struct overlay_changeset *ovcs)
+static int changeset_dup_entry_check(struct overlay_changeset *ovcs)
 {
-	struct of_changeset_entry *ce_1, *ce_2;
-	char *fn_1, *fn_2;
-	int name_match;
+	struct of_changeset_entry *ce_1;
+	int dup_entry = 0;
 
 	list_for_each_entry(ce_1, &ovcs->cset.entries, node) {
-
-		if (ce_1->action == OF_RECONFIG_ATTACH_NODE ||
-		    ce_1->action == OF_RECONFIG_DETACH_NODE) {
-
-			ce_2 = ce_1;
-			list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
-				if (ce_2->action == OF_RECONFIG_ATTACH_NODE ||
-				    ce_2->action == OF_RECONFIG_DETACH_NODE) {
-					/* inexpensive name compare */
-					if (!of_node_cmp(ce_1->np->full_name,
-					    ce_2->np->full_name)) {
-						/* expensive full path name compare */
-						fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
-						fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
-						name_match = !strcmp(fn_1, fn_2);
-						kfree(fn_1);
-						kfree(fn_2);
-						if (name_match) {
-							pr_err("ERROR: multiple overlay fragments add and/or delete node %pOF\n",
-							       ce_1->np);
-							return -EINVAL;
-						}
-					}
-				}
-			}
-		}
+		dup_entry |= find_dup_cset_node_entry(ovcs, ce_1);
+		dup_entry |= find_dup_cset_prop(ovcs, ce_1);

I think this is worse performance than before.

This now walks all entries when before it would
return -EINVAL directly when it found a match.

Yes, it is worse performance, but that is OK.

This is a check that is done when a devicetree overlay is applied.
If an error occurs then that means that the overlay was incorrectly
specified.  The file drivers/of/unittest-data/overlay_bad_add_dup_prop.dts
in this patch provides an example of how a bad overlay can be created.

Once an error was detected, the check could return immediately, or it
could continue to give a complete list of detected errors.  I chose to
give the complete list of detected errors.

-Frank