All of lore.kernel.org
 help / color / mirror / Atom feed
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>

[-- Attachment #1: Type: text/plain, Size: 1012 bytes --]

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

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=2328482.ElGaqSPkdT@sven-l14 \
    --to=sven@narfation.org \
    --cc=b.a.t.m.a.n@lists.open-mesh.org \
    --cc=dmantipov@yandex.ru \
    --cc=linus.luessing@c0d3.blue \
    --cc=netdev@vger.kernel.org \
    --cc=paulmck@kernel.org \
    --cc=rcu@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.