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From: Sven Eckelmann <sven@narfation.org>
To: "Paul E. McKenney" <paulmck@kernel.org>, b.a.t.m.a.n@lists.open-mesh.org
Cc: b.a.t.m.a.n@lists.open-mesh.org,
	"Dmitry Antipov" <dmantipov@yandex.ru>,
	netdev@vger.kernel.org, rcu@vger.kernel.org,
	"Linus Lüssing" <linus.luessing@c0d3.blue>
Subject: Re: [PATCH] Revert "batman-adv: prefer kfree_rcu() over call_rcu() with free-only callbacks"
Date: Wed, 12 Jun 2024 20:22:49 +0200	[thread overview]
Message-ID: <2328482.ElGaqSPkdT@sven-l14> (raw)
In-Reply-To: <ZmnNfU44NekafjA_@sellars>

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On Wednesday, 12 June 2024 18:31:57 CEST Linus Lüssing wrote:
> On Wed, Jun 12, 2024 at 09:06:25AM -0700, Paul E. McKenney wrote:
> > We are looking into nice ways of solving this, but in the meantime,
> > yes, if you are RCU-freeing slab objects into a slab that is destroyed
> > at module-unload time, you currently need to stick with call_rcu()
> > and rcu_barrier().
> >
> > We do have some potential solutions to allow use of kfree_rcu() with
> > this sort of slab, but they are still strictly potential.
> >
> > Apologies for my having failed to foresee this particular trap!
> 
> No worries, thanks for the help and clarification! This at least
> restored my sanity, was starting to doubt my understanding of RCU
> and the batman-adv code the longer I tried to find the issue in
> batman-adv :D.

Thanks Linus and Paul. I've queued up the revert. But feel free to submit a 
version with updated text in case you want to incorporate information from 
this thread.

Kind regards,
	Sven

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  reply	other threads:[~2024-06-12 18:23 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-12 13:33 [PATCH] Revert "batman-adv: prefer kfree_rcu() over call_rcu() with free-only callbacks" Linus Lüssing
2024-06-12 14:06 ` Paul E. McKenney
2024-06-12 14:39   ` Linus Lüssing
2024-06-12 14:54     ` Linus Lüssing
2024-06-12 16:06       ` Paul E. McKenney
2024-06-12 16:31         ` Linus Lüssing
2024-06-12 18:22           ` Sven Eckelmann [this message]
2024-06-12 15:01     ` Paul E. McKenney
2024-06-12 16:25     ` Uladzislau Rezki

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