linux-kernel - Re: [PATCH v2] jbd2: allocate lock_class_key for jbd2

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

Message-ID: <8482e4e3-b233-4540-aa47-4573ee87fe96@I-love.SAKURA.ne.jp>
Date: Fri, 31 Oct 2025 20:28:34 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: Jan Kara <jack@...e.cz>
Cc: "Theodore Ts'o" <tytso@....edu>, Andreas Dilger <adilger.kernel@...ger.ca>,
        Jan Kara <jack@...e.com>,
        "linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2] jbd2: allocate lock_class_key for jbd2_handle
 dynamically

Who can take this patch?

On 2025/10/23 16:59, Jan Kara wrote:
> On Wed 22-10-25 20:11:37, Tetsuo Handa wrote:
>> syzbot is reporting possibility of deadlock due to sharing lock_class_key
>> for jbd2_handle across ext4 and ocfs2. But this is a false positive, for
>> one disk partition can't have two filesystems at the same time.
>>
>> Reported-by: syzbot+6e493c165d26d6fcbf72@...kaller.appspotmail.com
>> Closes: https://syzkaller.appspot.com/bug?extid=6e493c165d26d6fcbf72
>> Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
>> Tested-by: syzbot+6e493c165d26d6fcbf72@...kaller.appspotmail.com
> 
> Thanks! Tha patch looks good. Feel free to add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>
> 
> 								Honza
> 
>> ---
>>  fs/jbd2/journal.c    | 6 ++++--
>>  include/linux/jbd2.h | 6 ++++++
>>  2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
>> index d480b94117cd..f43474002f50 100644
>> --- a/fs/jbd2/journal.c
>> +++ b/fs/jbd2/journal.c
>> @@ -1521,7 +1521,6 @@ static journal_t *journal_init_common(struct block_device *bdev,
>>  			struct block_device *fs_dev,
>>  			unsigned long long start, int len, int blocksize)
>>  {
>> -	static struct lock_class_key jbd2_trans_commit_key;
>>  	journal_t *journal;
>>  	int err;
>>  	int n;
>> @@ -1530,6 +1529,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
>>  	if (!journal)
>>  		return ERR_PTR(-ENOMEM);
>>  
>> +	lockdep_register_key(&journal->jbd2_trans_commit_key);
>>  	journal->j_blocksize = blocksize;
>>  	journal->j_dev = bdev;
>>  	journal->j_fs_dev = fs_dev;
>> @@ -1560,7 +1560,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
>>  	journal->j_max_batch_time = 15000; /* 15ms */
>>  	atomic_set(&journal->j_reserved_credits, 0);
>>  	lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
>> -			 &jbd2_trans_commit_key, 0);
>> +			 &journal->jbd2_trans_commit_key, 0);
>>  
>>  	/* The journal is marked for error until we succeed with recovery! */
>>  	journal->j_flags = JBD2_ABORT;
>> @@ -1611,6 +1611,7 @@ static journal_t *journal_init_common(struct block_device *bdev,
>>  	kfree(journal->j_wbuf);
>>  	jbd2_journal_destroy_revoke(journal);
>>  	journal_fail_superblock(journal);
>> +	lockdep_unregister_key(&journal->jbd2_trans_commit_key);
>>  	kfree(journal);
>>  	return ERR_PTR(err);
>>  }
>> @@ -2187,6 +2188,7 @@ int jbd2_journal_destroy(journal_t *journal)
>>  		jbd2_journal_destroy_revoke(journal);
>>  	kfree(journal->j_fc_wbuf);
>>  	kfree(journal->j_wbuf);
>> +	lockdep_unregister_key(&journal->jbd2_trans_commit_key);
>>  	kfree(journal);
>>  
>>  	return err;
>> diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
>> index 43b9297fe8a7..f5eaf76198f3 100644
>> --- a/include/linux/jbd2.h
>> +++ b/include/linux/jbd2.h
>> @@ -1253,6 +1253,12 @@ struct journal_s
>>  	 */
>>  	struct lockdep_map	j_trans_commit_map;
>>  #endif
>> +	/**
>> +	 * @jbd2_trans_commit_key:
>> +	 *
>> +	 * "struct lock_class_key" for @j_trans_commit_map
>> +	 */
>> +	struct lock_class_key	jbd2_trans_commit_key;
>>  
>>  	/**
>>  	 * @j_fc_cleanup_callback:
>> -- 
>> 2.47.3
>>
>>