From: Jeongjun Park <aha310510@gmail.com>
To: jirislaby@kernel.org
Cc: davem@davemloft.net, edumazet@google.com,
gregkh@linuxfoundation.org, kuba@kernel.org,
linux-kernel@vger.kernel.org, linux-ppp@vger.kernel.org,
netdev@vger.kernel.org, pabeni@redhat.com,
syzbot+393d0ef63475d9bb1f16@syzkaller.appspotmail.com,
syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH net,v3] net: ppp: Fix deadlock caused by unsafe-irq lock in ap_get()
Date: Mon, 22 Apr 2024 17:58:01 +0900 [thread overview]
Message-ID: <20240422085801.140509-1-aha310510@gmail.com> (raw)
In-Reply-To: <bb5c1fd1-c3e7-4aaf-b28d-a45479ff0815@kernel.org>
Jiri Slaby wrote:
> OK, but read_unlock_irq() is not the right way to do it. It would enable
> irqs unconditionally, so serial8250_tx_chars() would not thank you in
> the above call chain.
>
> Plus the issues Jakub had with the patch.
>
> And what about ppp_synctty?
Hmm... If the problem is the case of calling the function in
serial8250_tx_chars(), I think it can be solved by continuing to use
read_lock() in ppp_asynctty_wakeup() and getting the ap by not calling
ap_get().
If I do this, will I be able to apply the existing patch to ap_get()?
Thanks.
prev parent reply other threads:[~2024-04-22 8:58 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 2:34 [syzbot] [ppp?] possible deadlock in ppp_asynctty_receive (2) syzbot
2024-04-19 18:12 ` [PATCH net,v2] net: ppp: Fix deadlock caused by unsafe-irq lock in ap_get() Jeongjun Park
2024-04-19 18:38 ` [PATCH net,v3] " Jeongjun Park
2024-04-20 0:31 ` Jakub Kicinski
2024-04-22 6:39 ` Jiri Slaby
2024-04-22 7:18 ` Jeongjun Park
2024-04-22 7:29 ` Jiri Slaby
2024-04-22 8:58 ` Jeongjun Park [this message]
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