Fix ubsan: shift exponent is too large

When running libzpool with the Undefined Behavior Sanitizer (ubsan) enabled, a zpool create causes a run-time error: module/zfs/vdev_label.c:600:14: runtime error: shift exponent 64 is too large for 64-bit type 'long long unsigned int'` in vdev_config_generate() Fix is to convert vdev_removal_max_span to its base-2 logarithm, using highbit64(), and then compare the "shifts". Fixes #9744 Signed-off-by: Chuck Tuffli <[email protected]>
openzfs · Oct 7, 2020 · 75a6156 · 75a6156
1 parent a76e4e6
commit 75a6156
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
@@ -613,7 +613,8 @@ vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats,
 			 * as a single mapping.
 			 */
 			for (int i = 0; i < RANGE_TREE_HISTOGRAM_SIZE; i++) {
-				if (1ULL << (i + 1) < vdev_removal_max_span) {
+				if (i + 1 < highbit64(vdev_removal_max_span)
+				    - 1) {
 					to_alloc +=
 					    vd->vdev_mg->mg_histogram[i] <<
 					    (i + 1);