linux-kernel - Re: [PATCH] rxrpc_find_service_conn_rcu: use read_seqbegin() rather than read_seqbegin_or

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

Message-ID: <20231101205238.GI1957730@ZenIV>
Date:   Wed, 1 Nov 2023 20:52:38 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Oleg Nesterov <oleg@...hat.com>
Cc:     David Howells <dhowells@...hat.com>,
        Marc Dionne <marc.dionne@...istor.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Chuck Lever <chuck.lever@...cle.com>,
        linux-afs@...ts.infradead.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] rxrpc_find_service_conn_rcu: use read_seqbegin() rather
 than read_seqbegin_or_lock()

On Wed, Nov 01, 2023 at 09:23:03PM +0100, Oleg Nesterov wrote:

> Yes this is confusing. Again, even the documentation is wrong! That is why
> I am trying to remove the misuse of read_seqbegin_or_lock(), then I am going
> to change the semantics of need_seqretry() to enforce the locking on the 2nd
> pass.

What for?  Sure, documentation needs to be fixed, but *not* in direction you
suggested in that patch.

Why would you want to force that "switch to locked on the second pass" policy
on every possible caller?