When running with UndefinedBehaviorSanitizer, the tests produce the following
error:
radix-tree.c:836:30: runtime error: shift exponent 18446744073709551613
is too large for 64-bit type 'unsigned long'
(That's a negative shift exponent represented as an unsigned long.)
Even though the value is discarded in those cases, it's still undefined
behavior; see the C99 standard, section 6.5.7, paragraph three: "If the
value of the right operand is negative [...] the behavior is undefined."
Signed-off-by: Adam Buchbinder <abuchbinder@google.com>
---
radix-tree.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/radix-tree.c b/radix-tree.c
index 4f295fc..7457944 100644
--- a/radix-tree.c
+++ b/radix-tree.c
@@ -833,10 +833,10 @@ int radix_tree_tagged(struct radix_tree_root *root,
unsigned int tag)
static unsigned long __maxindex(unsigned int height)
{
unsigned int tmp = height * RADIX_TREE_MAP_SHIFT;
- unsigned long index = (~0UL >> (RADIX_TREE_INDEX_BITS - tmp - 1))
>> 1;
+ unsigned long index = ~0UL;
- if (tmp >= RADIX_TREE_INDEX_BITS)
- index = ~0UL;
+ if (tmp < RADIX_TREE_INDEX_BITS)
+ index = (index >> (RADIX_TREE_INDEX_BITS - tmp - 1)) >> 1;
return index;
}
--
2.0.0.526.g5318336
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