From: Jakub Kicinski <kuba@kernel.org>
To: Breno Leitao <leitao@debian.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Andrew Lunn <andrew+netdev@lunn.ch>,
David Ahern <dsahern@kernel.org>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
Eric Dumazet <eric.dumazet@gmail.com>,
kuniyu@amazon.co.jp, ushankar@purestorage.com,
Kuniyuki Iwashima <kuniyu@amazon.com>
Subject: Re: [PATCH net v4 2/2] arp: switch to dev_getbyhwaddr() in arp_req_set_public()
Date: Tue, 18 Feb 2025 06:29:20 -0800 [thread overview]
Message-ID: <20250218062920.40aaaa6a@kernel.org> (raw)
In-Reply-To: <20250218-debonair-smoky-sparrow-97e07f@leitao>
On Tue, 18 Feb 2025 01:36:30 -0800 Breno Leitao wrote:
> On Mon, Feb 17, 2025 at 04:33:44PM -0800, Jakub Kicinski wrote:
> > On Thu, 13 Feb 2025 04:42:38 -0800 Breno Leitao wrote:
> > > The arp_req_set_public() function is called with the rtnl lock held,
> > > which provides enough synchronization protection. This makes the RCU
> > > variant of dev_getbyhwaddr() unnecessary. Switch to using the simpler
> > > dev_getbyhwaddr() function since we already have the required rtnl
> > > locking.
> > >
> > > This change helps maintain consistency in the networking code by using
> > > the appropriate helper function for the existing locking context.
> >
> > I think you should make it clearer whether this fixes a splat with
> > PROVE_RCU_LIST=y
>
> This one doesn't fix the splat in fact, since rtnl lock was held, and it
> is moving from dev_getbyhwaddr_rcu() to dev_getbyhwaddr(), since rtnl
> lock was held.
Are you sure? I don't see the RCU lock being taken on the path that
ends up here. arp_ioctl() -> arp_req_set() -> arp_req_set_public()
next prev parent reply other threads:[~2025-02-18 14:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-13 12:42 [PATCH net v4 0/2] net: core: improvements to device lookup by hardware address Breno Leitao
2025-02-13 12:42 ` [PATCH net v4 1/2] net: Add non-RCU dev_getbyhwaddr() helper Breno Leitao
2025-02-14 5:49 ` Kuniyuki Iwashima
2025-02-18 0:32 ` Jakub Kicinski
2025-02-13 12:42 ` [PATCH net v4 2/2] arp: switch to dev_getbyhwaddr() in arp_req_set_public() Breno Leitao
2025-02-18 0:33 ` Jakub Kicinski
2025-02-18 9:36 ` Breno Leitao
2025-02-18 14:29 ` Jakub Kicinski [this message]
2025-02-18 16:27 ` Breno Leitao
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