Btrfs: just free dummy extent buffers

If we fail during our sanity tests we could get NULL deref's because we unload
the module before the dummy extent buffers are free'd via RCU.  So check for
this case and just free the things directly.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 29850d4..d13cead 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4968,6 +4968,12 @@ static int release_extent_buffer(struct extent_buffer *eb)
 
                /* Should be safe to release our pages at this point */
                btrfs_release_extent_buffer_page(eb);
+#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
+               if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &eb->bflags))) {
+                       __free_extent_buffer(eb);
+                       return 1;
+               }
+#endif
                call_rcu(&eb->rcu_head, btrfs_release_extent_buffer_rcu);
                return 1;
        }