linux-kernel - Re: [PATCH] f2fs: add sanity check on ei.len in __update_extent_tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <b473d03c-79d4-4c49-abe3-b41ff64982c3@kernel.org>
Date: Thu, 18 Sep 2025 10:15:57 +0800
From: Chao Yu <chao@...nel.org>
To: Jaegeuk Kim <jaegeuk@...nel.org>
Cc: chao@...nel.org, linux-f2fs-devel@...ts.sourceforge.net,
 linux-kernel@...r.kernel.org, wangzijie <wangzijie1@...or.com>
Subject: Re: [PATCH] f2fs: add sanity check on ei.len in
 __update_extent_tree_range()

On 9/18/25 00:40, Jaegeuk Kim wrote:
> Do we need this?

I think so, it can provide a way to dump more information to troubleshoot
in which function we're trying to update w/ a zero-sized extent.

Thanks,

> 
> On 09/16, Chao Yu wrote:
>> Add a sanity check in __update_extent_tree_range() to detect any
>> zero-sized extent update.
>>
>> Signed-off-by: wangzijie <wangzijie1@...or.com>
>> Signed-off-by: Chao Yu <chao@...nel.org>
>> ---
>>  fs/f2fs/extent_cache.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
>> index 199c1e7a83ef..3070d1cb0676 100644
>> --- a/fs/f2fs/extent_cache.c
>> +++ b/fs/f2fs/extent_cache.c
>> @@ -664,6 +664,15 @@ static void __update_extent_tree_range(struct inode *inode,
>>  	if (!et)
>>  		return;
>>  
>> +	if (unlikely(len == 0)) {
>> +		f2fs_err_ratelimited(sbi, "%s: extent len is zero, type: %d, "
>> +			"extent [%u, %u, %u], age [%llu, %llu]",
>> +			__func__, type, tei->fofs, tei->blk, tei->len,
>> +			tei->age, tei->last_blocks);
>> +		f2fs_bug_on(sbi, 1);
>> +		return;
>> +	}
>> +
>>  	if (type == EX_READ)
>>  		trace_f2fs_update_read_extent_tree_range(inode, fofs, len,
>>  						tei->blk, 0);
>> -- 
>> 2.49.0