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Message-ID: <0acd9312-a4d2-20f0-eeaf-d1410dca48e1@kernel.org>
Date:   Wed, 11 Jan 2023 10:54:49 +0100
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Subject: Re: [PATCH] tracing/osnoise: Use built-in RCU list checking
To:     Chuang Wang <nashuiliang@gmail.com>
Cc:     Steven Rostedt <rostedt@goodmis.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-kernel@vger.kernel.org
References: <20221227023036.784337-1-nashuiliang@gmail.com>
Content-Language: en-US
From:   Daniel Bristot de Oliveira <bristot@kernel.org>
In-Reply-To: <20221227023036.784337-1-nashuiliang@gmail.com>
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On 12/27/22 03:30, Chuang Wang wrote:
> list_for_each_entry_rcu() has built-in RCU and lock checking.
> 
> Pass cond argument to list_for_each_entry_rcu() to silence false lockdep
> warning when CONFIG_PROVE_RCU_LIST is enabled.
> 
> Execute as follow:
> 
>  [tracing]# echo osnoise > current_tracer
>  [tracing]# echo 1 > tracing_on
>  [tracing]# echo 0 > tracing_on
> 
> The trace_types_lock is held when osnoise_tracer_stop() or
> timerlat_tracer_stop() are called in the non-RCU read side section.
> So, pass lockdep_is_held(&trace_types_lock) to silence false lockdep
> warning.
> 
> Fixes: dae181349f1e ("tracing/osnoise: Support a list of trace_array *tr")
> Signed-off-by: Chuang Wang <nashuiliang@gmail.com>

Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>

Thanks!
-- Daniel