From: Baokun Li <libaokun1@huawei.com>
To: Theodore Ts'o <tytso@mit.edu>
Cc: "Luís Henriques" <lhenriques@suse.de>,
"Andreas Dilger" <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2] ext4: fix a NULL pointer when validating an inode bitmap
Date: Thu, 1 Dec 2022 14:20:09 +0800 [thread overview]
Message-ID: <f898b4d4-f1b2-ffc6-4859-39cc99459cce@huawei.com> (raw)
In-Reply-To: <Y4guSv6wHI1i+3Cz@mit.edu>
On 2022/12/1 12:32, Theodore Ts'o wrote:
> On Wed, Nov 30, 2022 at 11:20:11AM +0800, Baokun Li wrote:
>>> If we can protect against the problem by adding a check that has other
>>> value as well (such as making usre that when ext4_iget fetches a
>>> special inode, we enforce that i_links_couint must be > 0), maybe
>>> that's worth it.
>> Yes, but some special inodes allow i_links_couint to be zero,
>> such as the uninitialized boot load inode.
> That's a good point; but the only time when a special inode can
> validly have a zero i_links_count is when it has no blocks associated
> to it. Otherwise, when the file system releases the inode using
> iput() when the file system is unmounted, all of the blocks will get
> released when the inode is evicted. So we can have ext4_iget() allow
> fetching an inode if i_blocks[] is zeros. But if it has any blocks
> and i_links_count is non-zero, something must be terribly wrong with
> that inode.
>
> Cheers,
>
> - Ted
>
Totally agree! That sounds good!
--
With Best Regards,
Baokun Li
.
next prev parent reply other threads:[~2022-12-01 6:20 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-10 14:20 [PATCH] ext4: fix a NULL pointer when validating an inode bitmap Luís Henriques
2022-10-11 15:56 ` [PATCH v2] " Luís Henriques
2022-11-06 0:32 ` Theodore Ts'o
2022-11-08 14:06 ` Luís Henriques
2022-11-28 22:28 ` Theodore Ts'o
2022-11-29 3:18 ` Baokun Li
2022-11-29 21:00 ` Theodore Ts'o
2022-11-30 3:20 ` Baokun Li
2022-12-01 4:32 ` Theodore Ts'o
2022-12-01 6:20 ` Baokun Li [this message]
2022-10-12 13:13 ` [PATCH v2] ext4: fix BUG_ON() when directory entry has invalid rec_len Luís Henriques
2022-10-12 13:16 ` Luís Henriques
2022-10-12 14:21 ` Theodore Ts'o
2022-10-12 15:18 ` Luís Henriques
2022-11-06 6:16 ` Theodore Ts'o
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