zhack: Fix importing large allocation profiles on small pools (#18256)

0mp · web-flow · commit 3408332d7154 · 2026-02-24T10:24:22.000-08:00
This patch fixes a segmentation fault in zhack metaslab leak which might be triggered by feeding zhack with a fragmentation profile that's exported from a pool larger than the target pool. Fixes: 8f15d2e Sponsored-by: Klara, Inc. Sponsored-by: Wasabi Technology, Inc. Reviewed-by: Paul Dagnelie <paul.dagnelie@klarasystems.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Mateusz Piotrowski <mateusz.piotrowski@klarasystems.com>
diff --git a/cmd/zhack.c b/cmd/zhack.c
@@ -745,8 +745,11 @@ zhack_do_metaslab_leak(int argc, char **argv)
 			    &start, &size), ==, 2);
 
 			ASSERT(vd);
-			metaslab_t *cur =
-			    vd->vdev_ms[start >> vd->vdev_ms_shift];
+			size_t idx;
+			idx = start >> vd->vdev_ms_shift;
+			if (idx >= vd->vdev_ms_count)
+				continue;
+			metaslab_t *cur = vd->vdev_ms[idx];
 			if (prev != cur) {
 				if (prev) {
 					dmu_tx_commit(tx);
