fs/btrfs/ref-verify.c:322:12-14: ERROR: reference preceded by free on line 321 (fwd)

It does not look correct to access &be->node on line 322 after freeing be on line 321.

julia

---------- Forwarded message ----------
Date: Fri, 1 Sep 2017 07:41:26 +0800
From: kbuild test robot <[email protected]>
To: [email protected]
Cc: Julia Lawall <[email protected]>
Subject: [josef-btrfs:btrfs-readdir 4/5] fs/btrfs/ref-verify.c:322:12-14: ERROR:
reference preceded by free on line 321

CC: [email protected]
CC: [email protected]
TO: Josef Bacik <[email protected]>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git btrfs-readdir
head:   707c82dec33ba199538c4b20885873c32c0c4259
commit: b5bfaee4fb7028e8ac44e1feab4d99b917b876d7 [4/5] Btrfs: add a extent ref verify tool

:::::: branch date: 5 hours ago
:::::: commit date: 8 hours ago

# https://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git/commit/?id=b5bfaee4fb7028e8ac44e1feab4d99b917b876d7
git remote add josef-btrfs https://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next.git
git remote update josef-btrfs
git checkout b5bfaee4fb7028e8ac44e1feab4d99b917b876d7
vim +322 fs/btrfs/ref-verify.c

b5bfaee4 Josef Bacik 2014-05-09  284
b5bfaee4 Josef Bacik 2014-05-09  285  static struct block_entry *add_block_entry(struct btrfs_root *root, u64 bytenr,
b5bfaee4 Josef Bacik 2014-05-09  286  					   u64 len, u64 root_objectid)
b5bfaee4 Josef Bacik 2014-05-09  287  {
b5bfaee4 Josef Bacik 2014-05-09  288  	struct btrfs_fs_info *fs_info = root->fs_info;
b5bfaee4 Josef Bacik 2014-05-09  289  	struct block_entry *be = NULL, *exist;
b5bfaee4 Josef Bacik 2014-05-09  290  	struct root_entry *re = NULL;
b5bfaee4 Josef Bacik 2014-05-09  291
b5bfaee4 Josef Bacik 2014-05-09  292  	re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
b5bfaee4 Josef Bacik 2014-05-09  293  	be = kmalloc(sizeof(struct block_entry), GFP_NOFS);
b5bfaee4 Josef Bacik 2014-05-09  294  	if (!be || !re) {
b5bfaee4 Josef Bacik 2014-05-09  295  		kfree(re);
b5bfaee4 Josef Bacik 2014-05-09  296  		kfree(be);
b5bfaee4 Josef Bacik 2014-05-09  297  		return ERR_PTR(-ENOMEM);
b5bfaee4 Josef Bacik 2014-05-09  298  	}
b5bfaee4 Josef Bacik 2014-05-09  299  	be->bytenr = bytenr;
b5bfaee4 Josef Bacik 2014-05-09  300  	be->len = len;
b5bfaee4 Josef Bacik 2014-05-09  301
b5bfaee4 Josef Bacik 2014-05-09  302  	re->root_objectid = root_objectid;
b5bfaee4 Josef Bacik 2014-05-09  303  	re->num_refs = 0;
b5bfaee4 Josef Bacik 2014-05-09  304
b5bfaee4 Josef Bacik 2014-05-09  305  	spin_lock(&fs_info->ref_verify_lock);
b5bfaee4 Josef Bacik 2014-05-09  306  	exist = insert_block_entry(&fs_info->block_tree, be);
b5bfaee4 Josef Bacik 2014-05-09  307  	if (exist) {
b5bfaee4 Josef Bacik 2014-05-09  308  		update_block_entry(root, exist, re);
b5bfaee4 Josef Bacik 2014-05-09  309  		kfree(be);
b5bfaee4 Josef Bacik 2014-05-09  310  		be = exist;
b5bfaee4 Josef Bacik 2014-05-09  311  		goto out;
b5bfaee4 Josef Bacik 2014-05-09  312  	}
b5bfaee4 Josef Bacik 2014-05-09  313
b5bfaee4 Josef Bacik 2014-05-09  314  	be->num_refs = 1;
b5bfaee4 Josef Bacik 2014-05-09  315  	be->metadata = 0;
b5bfaee4 Josef Bacik 2014-05-09  316  	be->roots = RB_ROOT;
b5bfaee4 Josef Bacik 2014-05-09  317  	be->refs = RB_ROOT;
b5bfaee4 Josef Bacik 2014-05-09  318  	INIT_LIST_HEAD(&be->actions);
b5bfaee4 Josef Bacik 2014-05-09  319  	if (insert_root_entry(&be->roots, re)) {
b5bfaee4 Josef Bacik 2014-05-09  320  		kfree(re);
b5bfaee4 Josef Bacik 2014-05-09 @321  		kfree(be);
b5bfaee4 Josef Bacik 2014-05-09 @322  		rb_erase(&be->node, &fs_info->block_tree);
b5bfaee4 Josef Bacik 2014-05-09  323  		be = ERR_PTR(-EINVAL);
b5bfaee4 Josef Bacik 2014-05-09  324  		ASSERT(0);
b5bfaee4 Josef Bacik 2014-05-09  325  	}
b5bfaee4 Josef Bacik 2014-05-09  326  out:
b5bfaee4 Josef Bacik 2014-05-09  327  	spin_unlock(&fs_info->ref_verify_lock);
b5bfaee4 Josef Bacik 2014-05-09  328  	return be;
b5bfaee4 Josef Bacik 2014-05-09  329  }

b5bfaee4 Josef Bacik 2014-05-09 330

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