From: Qi Zheng <zhengqi.arch@bytedance.com>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Youling Tang <youling.tang@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Youling Tang <tangyouling@kylinos.cn>
Subject: Re: [PATCH] mm: list_lru: Fix NULL pointer dereference in list_lru_add()
Date: Mon, 15 Jul 2024 11:27:18 +0800 [thread overview]
Message-ID: <56a81429-4e1e-46f9-8844-acb1afd66952@bytedance.com> (raw)
In-Reply-To: <sd32qchit33aafht27utinrz5dizw62qbtwdmwbtugqrlglmtx@6aitsotgqnpi>
On 2024/7/12 12:07, Kent Overstreet wrote:
> On Fri, Jul 12, 2024 at 11:25:54AM GMT, Youling Tang wrote:
>> From: Youling Tang <tangyouling@kylinos.cn>
>>
>> Note that list_lru_from_memcg_idx() may return NULL, so it is necessary
>> to error handle the return value to avoid triggering NULL pointer
>> dereference BUG.
>>
>> The issue was triggered for discussion [1],
>> Link [1]: https://lore.kernel.org/linux-bcachefs/84de6cb1-57bd-42f7-8029-4203820ef0b4@linux.dev/T/#m901bb26cdb1d9d4bacebf0d034f0a5a712cc93a6
>
> I see no explanation for why this is the correct fix, and I doubt it is.
> What's the real reason for the NULL lru_list_one, and why doesn't this
> come up on other filesystems?
Agree, IIRC, the list_lru_one will be pre-allocated in the allocation
path of inode/dentry etc.
next prev parent reply other threads:[~2024-07-15 3:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-12 3:25 Youling Tang
2024-07-12 4:07 ` Kent Overstreet
2024-07-12 4:28 ` Youling Tang
2024-07-12 15:49 ` Kent Overstreet
2024-07-16 2:28 ` Youling Tang
2024-07-16 2:30 ` Kent Overstreet
2024-07-15 3:27 ` Qi Zheng [this message]
2024-07-17 2:25 ` Youling Tang
2024-07-17 2:37 ` Qi Zheng
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