From: Daniel Borkmann <daniel@iogearbox.net>
To: Allan Zhang <allanzhang@google.com>
Cc: songliubraving@fb.com, netdev@vger.kernel.org,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
Stanislav Fomichev <sdf@google.com>,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH 1/1] bpf: Fix bpf_event_output re-entry issue
Date: Fri, 27 Sep 2019 14:44:48 +0200 [thread overview]
Message-ID: <20190927124448.GA22184@pc-66.home> (raw)
In-Reply-To: <20190925234312.94063-2-allanzhang@google.com>
On Wed, Sep 25, 2019 at 04:43:12PM -0700, Allan Zhang wrote:
> BPF_PROG_TYPE_SOCK_OPS program can reenter bpf_event_output because it can
> be called from atomic and non-atomic contexts since we don't have
> bpf_prog_active to prevent it happen.
>
> This patch enables 3 level of nesting to support normal, irq and nmi
> context.
>
> We can easily reproduce the issue by running neper crr mode with 100 flows
> and 10 threads from neper client side.
>
> Here is the whole stack dump:
[...]
>
> Fixes: a5a3a828cd00 ("bpf: add perf event notificaton support for sock_ops")
>
> Effort: BPF
> Signed-off-by: Allan Zhang <allanzhang@google.com>
> Reviewed-by: Stanislav Fomichev <sdf@google.com>
> Reviewed-by: Eric Dumazet <edumazet@google.com>
Applied, thanks!
prev parent reply other threads:[~2019-09-27 12:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 23:43 [PATCH 0/1] bpf: Fix bpf_event_output re-entry issue Allan Zhang
2019-09-25 23:43 ` [PATCH 1/1] " Allan Zhang
2019-09-26 16:20 ` John Fastabend
2019-09-27 12:44 ` Daniel Borkmann [this message]
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