btrfs: ref-verify: fix memory leaks in btrfs_ref_tree_mod()

stable inclusion
from stable-v6.6.5
commit 88287582f4d2dec54f934f3ab39cead5d880e6c2
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8N21P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=88287582f4d2dec54f934f3ab39cead5d880e6c2



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commit f91192cd68591c6b037da345bc9fcd5e50540358 upstream.

In btrfs_ref_tree_mod(), when !parent 're' was allocated through
kmalloc(). 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, 're' are not deallocated and may lead to
memory leaks.

For example: lookup_block_entry() for 'be' returns NULL, the out label
will be invoked. During that flow ref and 'ra' are freed but not 're',
which can potentially lead to a memory leak.

CC: stable@vger.kernel.org # 5.10+
Reported-and-tested-by:  <syzbot+d66de4cbf532749df35f@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=d66de4cbf532749df35f


Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>