From: Yonghong Song <yonghong.song@linux.dev>
To: Puranjay Mohan <puranjay@kernel.org>, Song Liu <song@kernel.org>,
Jiri Olsa <jolsa@kernel.org>, KP Singh <kpsingh@kernel.org>,
Matt Bobrowski <mattbobrowski@google.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, puranjay12@gmail.com
Subject: Re: [PATCH bpf] bpf: trace: send signals asynchronously if !preemptible
Date: Wed, 15 Jan 2025 08:55:30 -0800 [thread overview]
Message-ID: <34f1132b-43de-44d2-9bc0-e25b49598711@linux.dev> (raw)
In-Reply-To: <20250115103647.38487-1-puranjay@kernel.org>
On 1/15/25 2:36 AM, Puranjay Mohan wrote:
> BPF programs can execute in all kinds of contexts and when a program
> running in a non-preemptible context uses the bpf_send_signal() kfunc,
> it will cause issues because this kfunc can sleep.
>
> So change `irqs_disabled()` to `!preemptible()` that covers all edge
> cases: preempt_count() == 0 and irqs_disabled()
>
> Reported-by: syzbot+97da3d7e0112d59971de@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/all/67486b09.050a0220.253251.0084.GAE@google.com/
> Fixes: 1bc7896e9ef4 ("bpf: Fix deadlock with rq_lock in bpf_send_signal()")
> Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
next prev parent reply other threads:[~2025-01-15 16:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-15 10:36 [PATCH bpf] bpf: trace: send signals asynchronously if !preemptible Puranjay Mohan
2025-01-15 16:55 ` Yonghong Song [this message]
2025-01-15 21:50 ` patchwork-bot+netdevbpf
2025-01-21 1:26 ` Hou Tao
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