From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>, netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net-next 1/4] net: fix possible race in skb_attempt_defer_free()
Date: Mon, 16 May 2022 11:54:54 -0700 [thread overview]
Message-ID: <20220516115454.18fbc4e1@kernel.org> (raw)
In-Reply-To: <CANn89iJnS5Yyofudjbr7ZO5okRF67w1FRebQ71h3Bg75CA_L+Q@mail.gmail.com>
On Mon, 16 May 2022 11:24:40 -0700 Eric Dumazet wrote:
> On Mon, May 16, 2022 at 11:16 AM Jakub Kicinski <kuba@kernel.org> wrote:
> > If I'm reading this right this is useful for backports but in net-next
> > it really is a noop? The -EBUSY would be perfectly safe to ignore?
> > Just checking.
>
> Not sure I understand the question.
>
> trigger_rx_softirq() and friends were only in net-next, so there is no
> backport needed.
>
> Are you talking of calls from net_rps_send_ipi() ?
> These are fine, because we own an atomic bit (NAPI_STATE_SCHED).
Ah, I think I get it now. It was unclear what's the problem this patch
is solving this part of the commit message really is key:
> This is a common issue with smp_call_function_single_async().
> Callers must ensure correct synchronization and serialization.
smp_call_function_single_async() does not protect its own internal state
so we need to wrap it in our own locking (of some form thereof).
Sorry for the noise.
next prev parent reply other threads:[~2022-05-16 18:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-16 4:24 [PATCH net-next 0/4] net: polish skb defer freeing Eric Dumazet
2022-05-16 4:24 ` [PATCH net-next 1/4] net: fix possible race in skb_attempt_defer_free() Eric Dumazet
2022-05-16 18:15 ` Jakub Kicinski
2022-05-16 18:24 ` Eric Dumazet
2022-05-16 18:54 ` Jakub Kicinski [this message]
2022-05-16 4:24 ` [PATCH net-next 2/4] net: use napi_consume_skb() in skb_defer_free_flush() Eric Dumazet
2022-05-16 4:24 ` [PATCH net-next 3/4] net: add skb_defer_max sysctl Eric Dumazet
2022-05-16 20:39 ` Jakub Kicinski
2022-05-16 20:43 ` Eric Dumazet
2022-05-16 4:24 ` [PATCH net-next 4/4] net: call skb_defer_free_flush() before each napi_poll() Eric Dumazet
2022-05-16 18:21 ` Jakub Kicinski
2022-05-16 18:26 ` Eric Dumazet
2022-05-16 18:56 ` Jakub Kicinski
2022-05-16 10:40 ` [PATCH net-next 0/4] net: polish skb defer freeing patchwork-bot+netdevbpf
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