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-rw-r--r--lib/radix-tree.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 899fb750946..0ccbcdf7500 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -625,6 +625,8 @@ EXPORT_SYMBOL(radix_tree_tag_get);
*
* The function returns number of leaves where the tag was set and sets
* *first_indexp to the first unscanned index.
+ * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
+ * be prepared to handle that.
*/
unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
unsigned long *first_indexp, unsigned long last_index,
@@ -675,7 +677,8 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
next:
/* Go to next item at level determined by 'shift' */
index = ((index >> shift) + 1) << shift;
- if (index > last_index)
+ /* Overflow can happen when last_index is ~0UL... */
+ if (index > last_index || !index)
break;
if (tagged >= nr_to_tag)
break;