From: Simon Horman <horms@kernel.org>
To: Sabrina Dubroca <sd@queasysnail.net>
Cc: netdev@vger.kernel.org, Herbert Xu <herbert@gondor.apana.org.au>,
Steffen Klassert <steffen.klassert@secunet.com>
Subject: Re: [PATCH ipsec 2/2] espintcp: remove encap socket caching to avoid reference leak
Date: Fri, 11 Apr 2025 14:59:04 +0100 [thread overview]
Message-ID: <20250411135904.GG395307@horms.kernel.org> (raw)
In-Reply-To: <fba712655d0ec4003b28e432e5ba43d20f6d750f.1744206087.git.sd@queasysnail.net>
On Wed, Apr 09, 2025 at 03:59:57PM +0200, Sabrina Dubroca wrote:
> The current scheme for caching the encap socket can lead to reference
> leaks when we try to delete the netns.
>
> The reference chain is: xfrm_state -> enacp_sk -> netns
>
> Since the encap socket is a userspace socket, it holds a reference on
> the netns. If we delete the espintcp state (through flush or
> individual delete) before removing the netns, the reference on the
> socket is dropped and the netns is correctly deleted. Otherwise, the
> netns may not be reachable anymore (if all processes within the ns
> have terminated), so we cannot delete the xfrm state to drop its
> reference on the socket.
>
> This patch results in a small (~2% in my tests) performance
> regression.
>
> A GC-type mechanism could be added for the socket cache, to clear
> references if the state hasn't been used "recently", but it's a lot
> more complex than just not caching the socket.
Less is more :)
> Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2025-04-11 13:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-09 13:59 [PATCH ipsec 0/2] fix some leaks in espintcp Sabrina Dubroca
2025-04-09 13:59 ` [PATCH ipsec 1/2] espintcp: fix skb leaks Sabrina Dubroca
2025-04-11 13:58 ` Simon Horman
2025-04-09 13:59 ` [PATCH ipsec 2/2] espintcp: remove encap socket caching to avoid reference leak Sabrina Dubroca
2025-04-11 13:59 ` Simon Horman [this message]
2025-04-14 10:00 ` [PATCH ipsec 0/2] fix some leaks in espintcp Steffen Klassert
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