vfs: fix deadlock in file_remove_privs() on overlayfs
commit c1892c37769cf89c7e7ba57528ae2ccb5d153c9b upstream.
file_remove_privs() is called with inode lock on file_inode(), which
proceeds to calling notify_change() on file->f_path.dentry. Which triggers
the WARN_ON_ONCE(!inode_is_locked(inode)) in addition to deadlocking later
when ovl_setattr tries to lock the underlying inode again.
Fix this mess by not mixing the layers, but doing everything on underlying
dentry/inode.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 07a2daab49c5 ("ovl: Copy up underlying inode's ->i_mode to overlay inode")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/inode.c b/fs/inode.c
index 1be5f90..b0edef5 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1733,8 +1733,8 @@
*/
int file_remove_privs(struct file *file)
{
- struct dentry *dentry = file->f_path.dentry;
- struct inode *inode = d_inode(dentry);
+ struct dentry *dentry = file_dentry(file);
+ struct inode *inode = file_inode(file);
int kill;
int error = 0;
@@ -1742,7 +1742,7 @@
if (IS_NOSEC(inode))
return 0;
- kill = file_needs_remove_privs(file);
+ kill = dentry_needs_remove_privs(dentry);
if (kill < 0)
return kill;
if (kill)
