netdev - Re: [PATCH net-next v2 06/18] netfilter: nf_dup{4, 6}: Move duplication check to task

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] [day] [month] [year] [list]

Message-ID: <20250429092333.GG4198@noisy.programming.kicks-ass.net>
Date: Tue, 29 Apr 2025 11:23:33 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc: netdev@...r.kernel.org, linux-rt-devel@...ts.linux.dev,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Pablo Neira Ayuso <pablo@...filter.org>,
	Jozsef Kadlecsik <kadlec@...filter.org>,
	Ingo Molnar <mingo@...hat.com>, Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>
Subject: Re: [PATCH net-next v2 06/18] netfilter: nf_dup{4, 6}: Move
 duplication check to task_struct

On Mon, Apr 14, 2025 at 06:07:42PM +0200, Sebastian Andrzej Siewior wrote:
> nf_skb_duplicated is a per-CPU variable and relies on disabled BH for its
> locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
> this data structure requires explicit locking.
> 
> Due to the recursion involved, the simplest change is to make it a
> per-task variable.
> 
> Move the per-CPU variable nf_skb_duplicated to task_struct and name it
> in_nf_duplicate. Add it to the existing bitfield so it doesn't use
> additional memory.
> 
> Cc: Pablo Neira Ayuso <pablo@...filter.org>
> Cc: Jozsef Kadlecsik <kadlec@...filter.org>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Juri Lelli <juri.lelli@...hat.com>
> Cc: Vincent Guittot <vincent.guittot@...aro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@....com>
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Ben Segall <bsegall@...gle.com>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Valentin Schneider <vschneid@...hat.com>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> ---
>  include/linux/netfilter.h        | 11 -----------
>  include/linux/sched.h            |  1 +
>  net/ipv4/netfilter/ip_tables.c   |  2 +-
>  net/ipv4/netfilter/nf_dup_ipv4.c |  6 +++---
>  net/ipv6/netfilter/ip6_tables.c  |  2 +-
>  net/ipv6/netfilter/nf_dup_ipv6.c |  6 +++---
>  net/netfilter/core.c             |  3 ---
>  7 files changed, 9 insertions(+), 22 deletions(-)

Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>