Commit 3bbd0ef2 authored by Xiyu Yang's avatar Xiyu Yang Committed by Theodore Ts'o
Browse files

ext4: fix buffer_head refcnt leak when ext4_iget() fails 



ext4_orphan_get() invokes ext4_read_inode_bitmap(), which returns a
reference of the specified buffer_head object to "bitmap_bh" with
increased refcnt.

When ext4_orphan_get() returns, local variable "bitmap_bh" becomes
invalid, so the refcount should be decreased to keep refcount balanced.

The reference counting issue happens in one exception handling path of
ext4_orphan_get(). When ext4_iget() fails, the function forgets to
decrease the refcnt increased by ext4_read_inode_bitmap(), causing a
refcnt leak.

Fix this issue by calling brelse() when ext4_iget() fails.

Signed-off-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarXin Tan <tanxin.ctf@gmail.com>
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/1587618568-13418-1-git-send-email-xiyuyang19@fudan.edu.cn


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent c36a71b4

fs/ext4/ialloc.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -1246,6 +1246,7 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino) 
		ext4_error_err(sb, -err,

		ext4_error_err(sb, -err,

			       "couldn't read orphan inode %lu (err %d)",

			       "couldn't read orphan inode %lu (err %d)",

			       ino, err);

			       ino, err);

		brelse(bitmap_bh);

		return inode;

		return inode;

	}

	}