Commit 96fc3559 authored Apr 25, 2020 by Xiyu Yang Committed by Greg Kroah-Hartman May 27, 2020

configfs: fix config_item refcnt leak in configfs_rmdir()



[ Upstream commit 8aebfffacfa379ba400da573a5bf9e49634e38cb ]

configfs_rmdir() invokes configfs_get_config_item(), which returns a
reference of the specified config_item object to "parent_item" with
increased refcnt.

When configfs_rmdir() returns, local variable "parent_item" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
configfs_rmdir(). When down_write_killable() fails, the function forgets
to decrease the refcnt increased by configfs_get_config_item(), causing
a refcnt leak.

Fix this issue by calling config_item_put() when down_write_killable()
fails.

Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 19bba553

fs/configfs/dir.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -1537,6 +1537,7 @@ static int configfs_rmdir(struct inode dir, struct dentry dentry)
		spin_lock(&configfs_dirent_lock);
		configfs_detach_rollback(dentry);
		spin_unlock(&configfs_dirent_lock);
		config_item_put(parent_item);
		return -EINTR;
		}
		frag->frag_dead = true;