From: Jakub Kicinski <kuba@kernel.org>
To: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: <andrew+netdev@lunn.ch>, <davem@davemloft.net>,
<edumazet@google.com>, <horms@kernel.org>,
<netdev@vger.kernel.org>, <pabeni@redhat.com>, <sdf@fomichev.me>
Subject: Re: [PATCH net-next] net: let lockdep compare instance locks
Date: Thu, 15 May 2025 19:36:09 -0700 [thread overview]
Message-ID: <20250515193609.3da84ac3@kernel.org> (raw)
In-Reply-To: <20250516015114.40011-1-kuniyu@amazon.com>
On Thu, 15 May 2025 18:49:07 -0700 Kuniyuki Iwashima wrote:
> > +#ifdef CONFIG_DEBUG_NET_SMALL_RTNL
> > + /* It's okay to use per-netns rtnl_lock if devices share netns */
> > + if (net_eq(dev_net(dev_a), dev_net(dev_b)) &&
> > + lockdep_rtnl_net_is_held(dev_net(dev_a)))
>
> Do we need
>
> !from_cleanup_net()
>
> before lockdep_rtnl_net_is_held() ?
>
> __rtnl_net_lock() is not held in ops_exit_rtnl_list() and
> default_device_exit_batch() when calling unregister_netdevice_many().
Or do we need
if (from_cleanup_net())
return -1;
?
Is the thinking that once the big rtnl lock disappears in cleanup_net
the devices are safe to destroy without any locking because there can't
be any live users trying to access them?
next prev parent reply other threads:[~2025-05-16 2:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-16 1:24 [PATCH net-next] net: let lockdep compare instance locks Jakub Kicinski
2025-05-16 1:49 ` Kuniyuki Iwashima
2025-05-16 2:36 ` Jakub Kicinski [this message]
2025-05-16 2:59 ` Kuniyuki Iwashima
2025-05-16 15:22 ` Jakub Kicinski
2025-05-16 17:14 ` Jakub Kicinski
2025-05-16 17:50 ` Kuniyuki Iwashima
2025-05-16 17:50 ` Stanislav Fomichev
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