netdev - Re: [PATCH net v2] net: devmem: fix kernel panic when socket close after module unload

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: <20250507062321.4acdf9e6@kernel.org>
Date: Wed, 7 May 2025 06:23:21 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Taehee Yoo <ap420073@...il.com>
Cc: davem@...emloft.net, pabeni@...hat.com, edumazet@...gle.com,
 andrew+netdev@...n.ch, horms@...nel.org, almasrymina@...gle.com,
 sdf@...ichev.me, netdev@...r.kernel.org, asml.silence@...il.com,
 dw@...idwei.uk, skhawaja@...gle.com, willemb@...gle.com, jdamato@...tly.com
Subject: Re: [PATCH net v2] net: devmem: fix kernel panic when socket close
 after module unload

On Wed, 7 May 2025 13:55:44 +0900 Taehee Yoo wrote:
> So, it acquires a socket lock only for setting binding->dev to NULL,
> right? 

Yes.

BTW one more tiny nit pick:

 		net_devmem_unbind_dmabuf(binding);
+		mutex_unlock(&priv->lock);       << unlock
 		netdev_unlock(dev);
+		netdev_put(dev, &dev_tracker);
+		mutex_lock(&priv->lock);         << re-lock

The two marked ops are unnecessary. We only have to acquire the locks
in order. Its perfectly fine to release netdev_unlock() and keep holding
the socket lock.