From patchwork Mon May 28 17:34:05 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: vfs: avoid hang caused by attempting to rmdir an invalid file system Date: Mon, 28 May 2012 07:34:05 -0000 From: Theodore Ts'o X-Patchwork-Id: 161632 Message-Id: <1338226445-8911-1-git-send-email-tytso@mit.edu> To: linux-fsdevel@vger.kernel.org Cc: Ext4 Developers List , viro@ZenIV.linux.org.uk, sami.liedes@iki.fi, Theodore Ts'o If we rmdir a directory which is a hard link to '.', we will deadlock trying to grab the directory's i_mutex. Check for this condition and return EINVAL, which is what we return if the user attempts to rmdir "/foo/bar/." Signed-off-by: "Theodore Ts'o" --- fs/namei.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index 0062dd1..081f872 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2774,6 +2774,17 @@ static long do_rmdir(int dfd, const char __user *pathname) error = -ENOENT; goto exit3; } + if (nd.path.dentry->d_inode == dentry->d_inode) { + /* + * Corrupt file system where there is a symlink to + * '.'; treat it as if we are trying to rmdir '.' + * + * XXX Should we call into the low-level file system + * to request that the file system be marked corrupt? + */ + error = -EINVAL; + goto exit3; + } error = mnt_want_write(nd.path.mnt); if (error) goto exit3;