ocfs2: update d_splice_alias() return code checking

When commit d3556babd7 ("ocfs2: fix d_splice_alias() return code
checking") was merged into v3.18-rc3, d_splice_alias() was returning one
of a valid dentry, NULL or an ERR_PTR.

When commit b5ae6b15bd ("merge d_materialise_unique() into
d_splice_alias()") was merged into v3.19-rc1, d_splice_alias() started
returning -ELOOP as one of ERR_PTR values.

Now, when syzkaller mounts a crafted ocfs2 filesystem image that hits
d_splice_alias() == -ELOOP case from ocfs2_lookup(), ocfs2_lookup() fails
to handle -ELOOP case and generic_shutdown_super() hits "VFS: Busy inodes
after unmount" message.

Instead of calling ocfs2_dentry_attach_lock() or ocfs2_dentry_attach_gen()
when d_splice_alias() returned an ERR_PTR value, change ocfs2_lookup() to
bail out immediately.

Also, ocfs2_lookup() needs to call dupt() when ocfs2_dentry_attach_lock()
returned an ERR_PTR value.

Link: https://lkml.kernel.org/r/da5be67d-2a0b-4b93-85d6-42f3b7440135@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+1134d3a5b062e9665a7a@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=1134d3a5b062e9665a7a
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tetsuo Handa <penguin-kernel@i-love-sakura.ne.jp>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Tetsuo Handa 2025-06-30 19:21:31 +09:00 committed by Andrew Morton
parent ad0039db42
commit d0118d7d20

View File

@ -142,6 +142,8 @@ static struct dentry *ocfs2_lookup(struct inode *dir, struct dentry *dentry,
bail_add:
ret = d_splice_alias(inode, dentry);
if (IS_ERR(ret))
goto bail_unlock;
if (inode) {
/*
@ -154,15 +156,16 @@ bail_add:
* NOTE: This dentry already has ->d_op set from
* ocfs2_get_parent() and ocfs2_get_dentry()
*/
if (!IS_ERR_OR_NULL(ret))
if (ret)
dentry = ret;
status = ocfs2_dentry_attach_lock(dentry, inode,
OCFS2_I(dir)->ip_blkno);
if (status) {
mlog_errno(status);
if (ret)
dput(ret);
ret = ERR_PTR(status);
goto bail_unlock;
}
} else
ocfs2_dentry_attach_gen(dentry);