netdev - Re: [PATCH net] rxrpc: Restore removed timer deletion

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 PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 13 Apr 2022 18:41:12 +0100
From:   David Howells <dhowells@...hat.com>
To:     Eric Dumazet <edumazet@...gle.com>
Cc:     dhowells@...hat.com, netdev@...r.kernel.org,
        Marc Dionne <marc.dionne@...istor.com>,
        linux-afs@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net] rxrpc: Restore removed timer deletion

Eric Dumazet <edumazet@...gle.com> wrote:

> ok... so we have a timer and a work queue, both activating each other
> in kind of a ping pong ?

Yes.  I want to emit regular keepalive pokes.

> Any particular reason not using delayed works ?

Because there's a race between starting the keepalive timer when a new peer is
added and when the keepalive worker is resetting the timer for the next peer
in the list.  This is why I'm using timer_reduce().  delayed_work doesn't
currently have such a facility.  It's not simple to add because
try_to_grab_pending() as called from mod_delayed_work_on() cancels the timer -
which is not what I want it to do.

David