linux-kernel - Re: [PATCH] tls: fix missing memory barrier in tls

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Message-ID: <20231110114410.01cd3eb3@kernel.org>
Date:   Fri, 10 Nov 2023 11:44:10 -0800
From:   Jakub Kicinski <kuba@...nel.org>
To:     "Dae R. Jeong" <threeearcat@...il.com>
Cc:     borisp@...dia.com, john.fastabend@...il.com, davem@...emloft.net,
        edumazet@...gle.com, pabeni@...hat.com, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, ywchoi@...ys.kaist.ac.kr
Subject: Re: [PATCH] tls: fix missing memory barrier in tls_init

On Fri, 10 Nov 2023 19:57:23 +0900 Dae R. Jeong wrote:
> +	mutex_init(&ctx->tx_lock);
> +	ctx->sk_proto = READ_ONCE(sk->sk_prot);
> +	ctx->sk = sk;
>  	ctx->tx_conf = TLS_BASE;
>  	ctx->rx_conf = TLS_BASE;

TLS_BASE is 0, so there's no strong reason to move the rcu assign
after *x_conf init. It's already 0. You can replace the assignment
with WARN_ON(ctx->tx_conf != TLS_BASE) to make sure, and move that 
into tls_ctx_create() instead of removing that function.

FWIW make sure you read this before posting v2:

https://www.kernel.org/doc/html/next/process/maintainer-netdev.html