diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 9984c2d275..47b58b6c2e 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -1205,7 +1205,7 @@ static void
 hdr_l2only_dest(void *vbuf, void *unused)
 {
 	(void) unused;
-	arc_buf_hdr_t *hdr = vbuf;
+	arc_buf_hdr_t *hdr __maybe_unused = vbuf;
 
 	ASSERT(HDR_EMPTY(hdr));
 	arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS);