linux-kernel - Re: [PATCH] ocfs2: cancel dqi_sync

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Message-ID: <e1496ade-7505-47bb-ac96-4dd48e2e530f@linux.alibaba.com>
Date: Wed, 4 Sep 2024 11:27:47 +0800
From: Joseph Qi <joseph.qi@...ux.alibaba.com>
To: Heming Zhao <heming.zhao@...e.com>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: ocfs2-devel@...ts.linux.dev, linux-kernel@...r.kernel.org,
 syzbot+f7af59df5d6b25f0febd@...kaller.appspotmail.com
Subject: Re: [PATCH] ocfs2: cancel dqi_sync_work before freeing oinfo



On 9/4/24 10:56 AM, Heming Zhao wrote:
> On 9/4/24 10:09, Joseph Qi wrote:
>> ocfs2_global_read_info() will schedule dqi_sync_work. So any error
>> occurs after it, we have to cancel this delayed work first before
>> freeing oinfo, otherwise it will trigger the following warning with
>> CONFIG_DEBUG_OBJECTS_* enabled:
>>
>> ODEBUG: free active (active state 0) object: 00000000d8b0ce28 object type: timer_list hint: qsync_work_fn+0x0/0x16c
>>
>> Link: https://syzkaller.appspot.com/bug?extid=f7af59df5d6b25f0febd
>> Reported-by: syzbot+f7af59df5d6b25f0febd@...kaller.appspotmail.com
>> Tested-by: syzbot+f7af59df5d6b25f0febd@...kaller.appspotmail.com
>> Fixes: 171bf93ce11f ("ocfs2: Periodic quota syncing")
>> Cc: stable@...r.kernel.org
>> Signed-off-by: Joseph Qi <joseph.qi@...ux.alibaba.com>
>> ---
>>   fs/ocfs2/quota_local.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
>> index 8ce462c64c51..ebe0dbc8db4a 100644
>> --- a/fs/ocfs2/quota_local.c
>> +++ b/fs/ocfs2/quota_local.c
>> @@ -782,6 +782,7 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
>>           if (locked)
>>               ocfs2_inode_unlock(lqinode, 1);
>>           ocfs2_release_local_quota_bitmaps(&oinfo->dqi_chunk);
>> +        cancel_delayed_work_sync(&oinfo->dqi_sync_work);
>>           kfree(oinfo);
>>       }
>>       brelse(bh);
> 
> In my view, there is one problem:
> If ocfs2_global_read_info() returns error before ->dqi_sync_work is
> initialized, above code will trigger wild pointer error.
> 

You're right. Will update and send v2.

Thanks,
Joseph