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 for Android: free password hash cracker in your pocket

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

Message-ID: <rrtgpocnwhmi2muaw3uk44dgmnt3oqotx4ohutftknjkaucjkh@qp6d2v2oxftx>
Date: Fri, 31 Oct 2025 13:42:09 +0100
From: Jan Kara <jack@...e.cz>
To: Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc: Jan Kara <jack@...e.cz>, 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

On Fri 31-10-25 20:28:34, Tetsuo Handa wrote:
> Who can take this patch?

Ted should pick it up. He's in CC so I'm sure he'll eventually get to it
when gathering patches for the next merge window.

								Honza

> 
> 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
> >>
> >>
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR