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-rw-r--r--lib/Kconfig.debug5
-rw-r--r--lib/radix-tree.c5
2 files changed, 8 insertions, 2 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9e06b7f5ecf..1b4afd2e6ca 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -994,13 +994,16 @@ config FAULT_INJECTION_STACKTRACE_FILTER
config LATENCYTOP
bool "Latency measuring infrastructure"
+ depends on HAVE_LATENCYTOP_SUPPORT
+ depends on DEBUG_KERNEL
+ depends on STACKTRACE_SUPPORT
+ depends on PROC_FS
select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE
select SCHEDSTATS
select SCHED_DEBUG
- depends on HAVE_LATENCYTOP_SUPPORT
help
Enable this option if you want to use the LatencyTOP tool
to find out which userspace is blocking on what kernel operations.
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index e0ee8cb37e4..efd16fa80b1 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -634,6 +634,8 @@ 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,
@@ -708,7 +710,8 @@ 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;