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From: Florian Westphal <fw@strlen.de>
To: Phil Sutter <phil@nwl.cc>, Florian Westphal <fw@strlen.de>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	netfilter-devel@vger.kernel.org, Eric Garver <e@erig.me>
Subject: Re: [nf-next PATCH v3 01/16] netfilter: nf_tables: Keep deleted flowtable hooks until after RCU
Date: Thu, 12 Sep 2024 16:27:18 +0200	[thread overview]
Message-ID: <20240912142718.GD2892@breakpoint.cc> (raw)
In-Reply-To: <ZuLxRi8asgeW1oLB@orbyte.nwl.cc>

Phil Sutter <phil@nwl.cc> wrote:
> > nf_tables_flowtable_destroy() is called after the hook has been
> > unregisted (detached from nf_hook list) and rcu grace period elapsed.
> 
> Yes, I didn't find a caller which didn't synchronize_rcu() before
> calling it. Same applies to chain hooks, right?

Sigh, there is nft_flowtable_find_dev() which iterates the nft_hook
list from packet path.

So the syncrhonize_rcu is irrelevant as long as the entry
is linked up and this patch is correct as-is.

 list_del_rcu(&hook->list);
 kfree(hook);

is illegal, and I think this should add a helper that unlinks
and then frees the entry via kfree_rcu and converts all instances
of this pattern.

  reply	other threads:[~2024-09-12 14:27 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-12 12:21 [nf-next PATCH v3 00/16] Dynamic hook interface binding Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 01/16] netfilter: nf_tables: Keep deleted flowtable hooks until after RCU Phil Sutter
2024-09-12 13:32   ` Florian Westphal
2024-09-12 13:48     ` Phil Sutter
2024-09-12 14:27       ` Florian Westphal [this message]
2024-09-16  0:00     ` Pablo Neira Ayuso
2024-09-16 21:42       ` Pablo Neira Ayuso
2024-09-17 21:14   ` Pablo Neira Ayuso
2024-09-12 12:21 ` [nf-next PATCH v3 02/16] netfilter: nf_tables: Flowtable hook's pf value never varies Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 03/16] netfilter: nf_tables: Store user-defined hook ifname Phil Sutter
2024-09-12 12:56   ` Florian Westphal
2024-09-12 13:26     ` Phil Sutter
2024-09-12 13:38       ` Florian Westphal
2024-09-12 12:21 ` [nf-next PATCH v3 04/16] netfilter: nf_tables: Use stored ifname in netdev hook dumps Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 05/16] netfilter: nf_tables: Compare netdev hooks based on stored name Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 06/16] netfilter: nf_tables: Tolerate chains with no remaining hooks Phil Sutter
2024-10-31 14:01   ` Florian Westphal
2024-10-31 14:19     ` Phil Sutter
2024-10-31 14:37       ` Florian Westphal
2024-10-31 15:16         ` Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 07/16] netfilter: nf_tables: Introduce functions freeing nft_hook objects Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 08/16] netfilter: nf_tables: Introduce nft_hook_find_ops() Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 09/16] netfilter: nf_tables: Introduce nft_register_flowtable_ops() Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 10/16] netfilter: nf_tables: Have a list of nf_hook_ops in nft_hook Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 11/16] netfilter: nf_tables: chain: Respect NETDEV_REGISTER events Phil Sutter
2024-09-12 14:40   ` Florian Westphal
2024-09-12 15:05     ` Phil Sutter
2024-09-12 15:12       ` Florian Westphal
2024-09-12 15:41         ` Phil Sutter
2024-09-12 16:06           ` Florian Westphal
2024-09-12 16:25             ` Phil Sutter
2024-09-12 20:43               ` Florian Westphal
2024-09-13 11:42                 ` Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 12/16] netfilter: nf_tables: flowtable: " Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 13/16] netfilter: nf_tables: Handle NETDEV_CHANGENAME events Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 14/16] netfilter: nf_tables: Support wildcard netdev hook specs Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 15/16] netfilter: nf_tables: Add notications for hook changes Phil Sutter
2024-09-12 12:21 ` [nf-next PATCH v3 16/16] selftests: netfilter: Torture nftables netdev hooks Phil Sutter

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