From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Eric Sandeen <sandeen@sandeen.net>
Subject: Re: [PATCH 3/3] ext4: Avoid freeing inodes on dirty list
Date: Thu, 14 May 2020 10:57:44 -0400 [thread overview]
Message-ID: <20200514145744.GW1596452@mit.edu> (raw)
In-Reply-To: <20200421085445.5731-4-jack@suse.cz>
On Tue, Apr 21, 2020 at 10:54:45AM +0200, Jan Kara wrote:
> When we are evicting inode with journalled data, we may race with
> transaction commit in the following way:
>
> CPU0 CPU1
> jbd2_journal_commit_transaction() evict(inode)
> inode_io_list_del()
> inode_wait_for_writeback()
> process BJ_Forget list
> __jbd2_journal_insert_checkpoint()
> __jbd2_journal_refile_buffer()
> __jbd2_journal_unfile_buffer()
> if (test_clear_buffer_jbddirty(bh))
> mark_buffer_dirty(bh)
> __mark_inode_dirty(inode)
> ext4_evict_inode(inode)
> frees the inode
>
> This results in use-after-free issues in the writeback code (or
> the assertion added in the previous commit triggering).
>
> Fix the problem by removing inode from writeback lists once all the page
> cache is evicted and so inode cannot be added to writeback lists again.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
Applied, thanks.
- Ted
prev parent reply other threads:[~2020-05-14 14:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 8:54 ext4: Fix use after free issues with journalled data Jan Kara
2020-04-21 8:54 ` [PATCH 1/3] fs: Avoid leaving freed inode on dirty list Jan Kara
2020-04-25 6:42 ` Xiaoguang Wang
2020-04-27 10:05 ` Jan Kara
2020-04-21 8:54 ` [PATCH 2/3] writeback: Export inode_io_list_del() Jan Kara
2020-05-14 14:57 ` Theodore Y. Ts'o
2020-04-21 8:54 ` [PATCH 3/3] ext4: Avoid freeing inodes on dirty list Jan Kara
2020-05-14 14:57 ` Theodore Y. Ts'o [this message]
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