btrfs: ref-verify: fix memory leaks

In btrfs_ref_tree_mod(), 'ref' and 'ra' are allocated through kzalloc() and
kmalloc(), respectively. In the following code, if an error occurs, the
execution will be redirected to 'out' or 'out_unlock' and the function will
be exited. However, on some of the paths, 'ref' and 'ra' are not
deallocated, leading to memory leaks. For example, if 'action' is
BTRFS_ADD_DELAYED_EXTENT, add_block_entry() will be invoked. If the return
value indicates an error, the execution will be redirected to 'out'. But,
'ref' is not deallocated on this path, causing a memory leak.

To fix the above issues, deallocate both 'ref' and 'ra' before exiting from
the function when an error is encountered.

CC: stable@vger.kernel.org # 4.15+
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index b57f3618e58e305f5520dbf7f472df816180b8e4..454a1015d026b741ec1a1b168375755d6df5971a 100644 (file)
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -744,6 +744,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
                 */
                be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
                if (IS_ERR(be)) {
+                       kfree(ref);
                        kfree(ra);
                        ret = PTR_ERR(be);
                        goto out;
@@ -757,6 +758,8 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
                        "re-allocated a block that still has references to it!");
                        dump_block_entry(fs_info, be);
                        dump_ref_action(fs_info, ra);
+                       kfree(ref);
+                       kfree(ra);
                        goto out_unlock;
                }
 
@@ -819,6 +822,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 "dropping a ref for a existing root that doesn't have a ref on the block");
                                dump_block_entry(fs_info, be);
                                dump_ref_action(fs_info, ra);
+                               kfree(ref);
                                kfree(ra);
                                goto out_unlock;
                        }
@@ -834,6 +838,7 @@ int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
 "attempting to add another ref for an existing ref on a tree block");
                        dump_block_entry(fs_info, be);
                        dump_ref_action(fs_info, ra);
+                       kfree(ref);
                        kfree(ra);
                        goto out_unlock;
                }