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From: John Fastabend <john.fastabend@gmail.com>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiayuan Chen <jiayuan.chen@linux.dev>,
	cong.wang@bytedance.com, jakub@cloudflare.com,
	davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, horms@kernel.org, andrii@kernel.org,
	eddyz87@gmail.com, mykolal@fb.com, ast@kernel.org,
	daniel@iogearbox.net, martin.lau@linux.dev, song@kernel.org,
	yonghong.song@linux.dev, kpsingh@kernel.org, sdf@fomichev.me,
	haoluo@google.com, jolsa@kernel.org, shuah@kernel.org,
	mhal@rbox.co, sgarzare@redhat.com, netdev@vger.kernel.org,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, mrpre@163.com,
	syzbot+dd90a702f518e0eac072@syzkaller.appspotmail.com
Subject: Re: [PATCH bpf-next v1 1/3] bpf, sockmap: avoid using sk_socket after free
Date: Thu, 27 Feb 2025 12:57:15 -0800	[thread overview]
Message-ID: <20250227205641.n2zpm5yetkoopvcz@gmail.com> (raw)
In-Reply-To: <Z8DA8TqMEYNziiT9@pop-os.localdomain>

On 2025-02-27 11:45:53, Cong Wang wrote:
> On Wed, Feb 26, 2025 at 09:22:40PM +0800, Jiayuan Chen wrote:
> > Use RCU lock to protect sk_socket, preventing concurrent close and release
> > by another thread.
> > 
> > Because TCP/UDP are already within a relatively large critical section:
> > '''
> > ip_local_deliver_finish
> >   rcu_read_lock
> >   ip_protocol_deliver_rcu
> >       tcp_rcv/udp_rcv
> >   rcu_read_unlock
> > '''
> > 
> > Adding rcu_read_{un}lock() at the entrance and exit of sk_data_ready
> > will not increase performance overhead.
> > 
> > Reported-by: syzbot+dd90a702f518e0eac072@syzkaller.appspotmail.com
> > Closes: https://lore.kernel.org/bpf/6734c033.050a0220.2a2fcc.0015.GAE@google.com/
> > Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> 
> sock_def_readable() already acquires RCU read lock anyway.
> 
> Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>

Thanks.

Reviewed-by: John Fastabend <john.fastabend@gmail.com>

  reply	other threads:[~2025-02-27 20:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-26 13:22 [PATCH bpf-next v1 0/3] bpf: Fix use-after-free of sockmap Jiayuan Chen
2025-02-26 13:22 ` [PATCH bpf-next v1 1/3] bpf, sockmap: avoid using sk_socket after free Jiayuan Chen
2025-02-27 19:45   ` Cong Wang
2025-02-27 20:57     ` John Fastabend [this message]
2025-02-27 23:04   ` Martin KaFai Lau
2025-02-28  4:49     ` Jiayuan Chen
2025-02-26 13:22 ` [PATCH bpf-next v1 2/3] selftests/bpf: Add socketpair to create_pair to support unix socket Jiayuan Chen
2025-02-27 19:52   ` Cong Wang
2025-02-27 22:21     ` John Fastabend
2025-02-28  4:51       ` Jiayuan Chen
2025-02-28  4:51     ` Jiayuan Chen
2025-02-26 13:22 ` [PATCH bpf-next v1 3/3] selftests/bpf: Add edge case tests for sockmap Jiayuan Chen
2025-02-27 19:53   ` Cong Wang
2025-02-27 22:18   ` John Fastabend

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