diff --git a/kmod/src/segment.c b/kmod/src/segment.c
index 4e94760a..85e51c90 100644
--- a/kmod/src/segment.c
+++ b/kmod/src/segment.c
@@ -188,9 +188,15 @@ static int add_item_off(struct scoutfs_sb_info *sbi, int height)
 {
 	int len = offsetof(struct scoutfs_item, skip_next[height]);
 	int off = sbi->dirty_item_off;
+	int block_off;
 	int tail_free;
 
-	/* item's can't cross a block boundary */
+	/* items can't start in a block header */
+	block_off = off & SCOUTFS_BLOCK_MASK;
+	if (block_off < sizeof(struct scoutfs_block_header))
+		off += sizeof(struct scoutfs_block_header) - block_off;
+
+	/* items can't cross a block boundary */
 	tail_free = SCOUTFS_BLOCK_SIZE - (off & SCOUTFS_BLOCK_MASK);
 	if (tail_free < len)
 		off += tail_free + sizeof(struct scoutfs_block_header);
@@ -432,6 +438,8 @@ next_chunk:
 	item_off = add_item_off(sbi, height);
 	val_off = sub_val_off(sbi, bytes);
 
+	trace_printk("item_off %u val_off %u\n", item_off, val_off);
+
 	if (item_off > val_off) {
 		ret = scoutfs_finish_dirty_segment(sb);
 		if (ret)
diff --git a/kmod/src/skip.c b/kmod/src/skip.c
index 69bae2b8..c855ae49 100644
--- a/kmod/src/skip.c
+++ b/kmod/src/skip.c
@@ -81,12 +81,16 @@ struct skip_path {
  */
 static int invalid_item_off(u32 off)
 {
-	return off < ((SCOUTFS_BLOCK_SIZE * SCOUTFS_BLOOM_BLOCKS) +
-		      sizeof(struct scoutfs_item_block)) ||
-		(off & SCOUTFS_BLOCK_MASK) <
-			sizeof(struct scoutfs_block_header) ||
-		(off & SCOUTFS_BLOCK_MASK) >
-			(SCOUTFS_BLOCK_SIZE - sizeof(struct scoutfs_item));
+	if (off < ((SCOUTFS_BLOCK_SIZE * SCOUTFS_BLOOM_BLOCKS) +
+			sizeof(struct scoutfs_item_block)) ||
+	   (off & SCOUTFS_BLOCK_MASK) < sizeof(struct scoutfs_block_header) ||
+	   (off & SCOUTFS_BLOCK_MASK) >
+			(SCOUTFS_BLOCK_SIZE - sizeof(struct scoutfs_item))) {
+		trace_printk("invalid offset %u\n", off);
+		return 1;
+	}
+
+	return 0;
 }
 
 /*