From: John Ogness <john.ogness@linutronix.de>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
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>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] bpf: defer printk() inside __bpf_prog_run()
Date: Tue, 25 Jun 2024 16:23:51 +0206 [thread overview]
Message-ID: <87ed8lxg1c.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <345098dc-8cb4-4808-98cf-fa9ab3af4fc4@I-love.SAKURA.ne.jp>
On 2024-06-25, Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
> syzbot is reporting circular locking dependency inside __bpf_prog_run(),
> for fault injection calls printk() despite rq lock is already held.
>
> Guard __bpf_prog_run() using printk_deferred_{enter,exit}() (and
> preempt_{disable,enable}() if CONFIG_PREEMPT_RT=n) in order to defer any
> printk() messages.
Why is the reason for disabling preemption?
John Ogness
next prev parent reply other threads:[~2024-06-25 14:17 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-25 13:56 [PATCH] bpf: defer printk() inside __bpf_prog_run() Tetsuo Handa
2024-06-25 14:17 ` John Ogness [this message]
2024-06-25 15:07 ` Tetsuo Handa
2024-06-25 15:47 ` John Ogness
2024-06-25 16:05 ` Tetsuo Handa
2024-06-25 19:32 ` Alexei Starovoitov
2024-06-25 23:52 ` Tetsuo Handa
2024-06-25 23:56 ` Alexei Starovoitov
2024-06-26 0:02 ` Tetsuo Handa
2024-06-26 16:27 ` Steven Rostedt
2024-06-26 22:15 ` Tetsuo Handa
2024-06-26 22:33 ` Steven Rostedt
2024-06-26 23:08 ` Tetsuo Handa
2024-06-26 23:52 ` Alexei Starovoitov
2024-06-27 0:00 ` Tetsuo Handa
2024-06-27 0:09 ` Steven Rostedt
2024-06-27 0:21 ` Tetsuo Handa
2024-06-27 0:29 ` Steven Rostedt
2024-06-27 11:10 ` [PATCH] sched/core: defer printk() while rq lock is held Tetsuo Handa
2024-06-26 8:45 ` [PATCH] bpf: defer printk() inside __bpf_prog_run() Petr Mladek
2024-06-26 8:18 ` Petr Mladek
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