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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Guillaume Nault <gnault@redhat.com>
Cc: netdev@vger.kernel.org, linux-rt-devel@lists.linux.dev,
	linux-ppp@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	Clark Williams <clrkwllms@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Simon Horman <horms@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH net-next v2 1/1] ppp: Replace per-CPU recursion counter with lock-owner field
Date: Mon, 14 Jul 2025 22:01:39 +0200	[thread overview]
Message-ID: <20250714200139.tgfgVP1L@linutronix.de> (raw)
In-Reply-To: <aHUsB04j+uFrUkpd@debian>

On 2025-07-14 18:10:47 [+0200], Guillaume Nault wrote:
> On Thu, Jul 10, 2025 at 06:24:03PM +0200, Sebastian Andrzej Siewior wrote:
> > The per-CPU variable ppp::xmit_recursion is protecting against recursion
> > due to wrong configuration of the ppp channels. The per-CPU variable
> 
> I'd rather say that it's the ppp unit that is badly configured: it's
> the ppp unit that can creates the loop (as it creates a networking
> interface).

I can reword this.

> > index def84e87e05b2..0edc916e0a411 100644
> > --- a/drivers/net/ppp/ppp_generic.c
> > +++ b/drivers/net/ppp/ppp_generic.c
> > @@ -119,6 +119,11 @@ struct ppp_link_stats {
> >  	u64 tx_bytes;
> >  };
> >  
> > +struct ppp_xmit_recursion {
> > +	struct task_struct *owner;
> > +	local_lock_t bh_lock;
> > +};
> > +
> 
> This hunk conflicts with latest changes in net-next.

Thank you.

> Apart from the two minor comments above, the patch looks good to me.
> Thanks!

Okay. As of the people involved while this detection was added and
polished, do you have an opinion on v1?
	https://lore.kernel.org/all/20250627105013.Qtv54bEk@linutronix.de/

Sebastian

  reply	other threads:[~2025-07-14 20:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-10 16:24 [PATCH net-next v2 0/1] ppp: Replace per-CPU recursion counter with lock-owner field Sebastian Andrzej Siewior
2025-07-10 16:24 ` [PATCH net-next v2 1/1] " Sebastian Andrzej Siewior
2025-07-14 16:10   ` Guillaume Nault
2025-07-14 20:01     ` Sebastian Andrzej Siewior [this message]
2025-07-15 17:33       ` Guillaume Nault

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