From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
syzbot <syzkaller@googlegroups.com>,
Wang Yufen <wangyufen@huawei.com>
Subject: Re: [PATCH net] net: tun: call napi_schedule_prep() to ensure we own a napi
Date: Tue, 8 Nov 2022 17:40:57 -0800 [thread overview]
Message-ID: <20221108174057.2336512c@kernel.org> (raw)
In-Reply-To: <20221107180011.188437-1-edumazet@google.com>
On Mon, 7 Nov 2022 18:00:11 +0000 Eric Dumazet wrote:
> if (unlikely(headlen > skb_headlen(skb))) {
> + WARN_ON_ONCE(1);
> + err = -ENOMEM;
> dev_core_stats_rx_dropped_inc(tun->dev);
> +napi_busy:
> napi_free_frags(&tfile->napi);
> rcu_read_unlock();
> mutex_unlock(&tfile->napi_mutex);
> - WARN_ON(1);
> - return -ENOMEM;
> + return err;
> }
>
> - local_bh_disable();
> - napi_gro_frags(&tfile->napi);
> - napi_complete(&tfile->napi);
> - local_bh_enable();
> + if (likely(napi_schedule_prep(&tfile->napi))) {
> + local_bh_disable();
> + napi_gro_frags(&tfile->napi);
> + napi_complete(&tfile->napi);
> + local_bh_enable();
> + } else {
> + err = -EBUSY;
> + goto napi_busy;
This can only hit if someone else is trying to detach / napi_disable()
at the same time?
> + }
next prev parent reply other threads:[~2022-11-09 1:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 18:00 [PATCH net] net: tun: call napi_schedule_prep() to ensure we own a napi Eric Dumazet
2022-11-09 1:40 ` Jakub Kicinski [this message]
2022-11-09 1:45 ` Eric Dumazet
2022-11-09 2:00 ` patchwork-bot+netdevbpf
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