From: Hawkins Jiawei <yin31149@gmail.com>
To: dan.carpenter@oracle.com
Cc: davem@davemloft.net, dhowells@redhat.com, edumazet@google.com,
khalid.masum.92@gmail.com, kuba@kernel.org,
linux-afs@lists.infradead.org,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-kernel@vger.kernel.org, marc.dionne@auristor.com,
netdev@vger.kernel.org, pabeni@redhat.com, paskripkin@gmail.com,
syzbot+7f0483225d0c94cb3441@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com, yin31149@gmail.com
Subject: Re: [PATCH] rxrpc: fix bad unlock balance in rxrpc_do_sendmsg
Date: Mon, 22 Aug 2022 23:39:43 +0800 [thread overview]
Message-ID: <20220822153944.6204-1-yin31149@gmail.com> (raw)
In-Reply-To: <20220822140532.GF2695@kadam>
On Mon, 22 Aug 2022 at 22:06, Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Mon, Aug 22, 2022 at 07:55:27PM +0600, Khalid Masum wrote:
> > >
> > > /*
> > > + * @holding_mutex: An indication whether caller can still holds
> > > + * the call->user_mutex when returned to caller.
> >
> > Maybe we can use mutex_is_locked instead of using the holding_mutex
> > parameter to get whether call->user_mutex is still held.
>
> That doesn't work. What if there is contention for the lock and someone
> else took it. Locks under contention are sort of the whole point of
> locking so it's highly likely.
I trid this before, it doesn't work as Dan points out. I think
it seems that mutex_is_locked() only checks whether there is a task
holding the mutex, but do not check whether it is current task holding
mutex. I also tried lockdep_is_held(), lockdep_is_held() seems can detect
call->user_mutex is still held accurately, although this cannot be the patch.
next prev parent reply other threads:[~2022-08-22 15:41 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-10 10:37 [syzbot] WARNING: " syzbot
2022-08-21 12:57 ` [PATCH] rxrpc: fix " Hawkins Jiawei
2022-08-21 15:58 ` Khalid Masum
2022-08-21 16:42 ` Khalid Masum
2022-08-22 5:19 ` Hawkins Jiawei
2022-08-21 19:17 ` [syzbot] WARNING: " Khalid Masum
2022-08-21 22:29 ` syzbot
2022-08-22 8:48 ` [PATCH] rxrpc: fix " David Howells
2022-08-22 9:21 ` David Howells
2022-08-22 11:29 ` Hawkins Jiawei
2022-08-22 11:29 ` Hawkins Jiawei
2022-08-22 13:04 ` Hawkins Jiawei
2022-08-22 13:44 ` Dan Carpenter
2022-08-22 13:55 ` Khalid Masum
2022-08-22 14:05 ` Dan Carpenter
2022-08-22 15:39 ` Hawkins Jiawei [this message]
2022-08-22 16:00 ` Khalid Masum
2022-08-22 14:24 ` [syzbot] WARNING: " David Howells
2022-08-22 15:45 ` David Howells
2022-08-22 16:23 ` syzbot
2022-08-24 16:30 ` Marc Dionne
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