On 04/30/2018 11:15 AM, Qu Wenruo wrote:
For btrfs_print_tree(), if nr_items is corrupted, it can easily go
beyond extent buffer boundary.

Add extra nr_item check, and only print as many valid slots as possible.


Make sense.

Signed-off-by: Qu Wenruo <w...@suse.com>
---
  print-tree.c | 11 ++++++++++-
  1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/print-tree.c b/print-tree.c
index 31a851ef4413..55db80bebb2a 100644
--- a/print-tree.c
+++ b/print-tree.c
@@ -1376,6 +1376,11 @@ void btrfs_print_tree(struct extent_buffer *eb, int 
follow)
                btrfs_print_leaf(eb);
                return;
        }
+       /* We are crossing eb boundary, this node must be corrupted */
+       if (nr > BTRFS_NODEPTRS_PER_EXTENT_BUFFER(eb))
+               warning(
+               "node nr_items corrupted, has %u limit %u, continue print 
anyway",
+                       nr, BTRFS_NODEPTRS_PER_EXTENT_BUFFER(eb));
        printf("node %llu level %d items %d free %u generation %llu owner ",
               (unsigned long long)eb->start,
                btrfs_header_level(eb), nr,
@@ -1386,7 +1391,11 @@ void btrfs_print_tree(struct extent_buffer *eb, int 
follow)
        print_uuids(eb);
        fflush(stdout);
                
-               u64 blocknr = btrfs_node_blockptr(eb, i);
+               u64 blocknr;
+
+               if (i > BTRFS_NODEPTRS_PER_EXTENT_BUFFER(eb))
+                       break;

Should it be i >= BTRFS_NODEPTRS_PER_EXTENT_BUFFER(eb)?

Here BTRFS_NODEPTRS_PER_EXTENT_BUFFER() is called during iterations.
The judement can be calculated in advance like:

        ptr_num = BTRFS_NODEPTRS_PER_EXTENT_BUFFER(eb);
        ...
        for (i = 0; i < nr && i < ptr_num  ; i++) {

Thanks,
Su

+               blocknr = btrfs_node_blockptr(eb, i);
                btrfs_node_key(eb, &disk_key, i);
                btrfs_disk_key_to_cpu(&key, &disk_key);
                printf("\t");



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