Commit 37ea7b63 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

debugfs: debugfs_lookup() should return NULL if not found 



Lots of callers of debugfs_lookup() were just checking NULL to see if
the file/directory was found or not.  By changing this in ff9fb72b
("debugfs: return error values, not NULL") we caused some subsystems to
easily crash.

Fixes: ff9fb72b ("debugfs: return error values, not NULL")
Reported-by: default avatar <syzbot+b382ba6a802a3d242790@syzkaller.appspotmail.com>
Reported-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ff9fb72b

fs/debugfs/inode.c

+5 −5
Original line number Diff line number Diff line
@@ -254,8 +254,8 @@ MODULE_ALIAS_FS("debugfs"); 
 * @parent: a pointer to the parent dentry of the file.

 *

 * This function will return a pointer to a dentry if it succeeds.  If the file

 * doesn't exist or an error occurs, %ERR_PTR(-ERROR) will be returned.  The

 * returned dentry must be passed to dput() when it is no longer needed.

 * doesn't exist or an error occurs, %NULL will be returned.  The returned

 * dentry must be passed to dput() when it is no longer needed.

 *

 * If debugfs is not enabled in the kernel, the value -%ENODEV will be

 * returned.
@@ -265,17 +265,17 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent) 
	struct dentry *dentry;



	if (IS_ERR(parent))

		return parent;

		return NULL;



	if (!parent)

		parent = debugfs_mount->mnt_root;



	dentry = lookup_one_len_unlocked(name, parent, strlen(name));

	if (IS_ERR(dentry))

		return dentry;

		return NULL;

	if (!d_really_is_positive(dentry)) {

		dput(dentry);

		return ERR_PTR(-EINVAL);

		return NULL;

	}

	return dentry;

}