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Date: Thu, 17 Apr 2025 10:18:04 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH v2] tracing: Record trace_clock and recover when reboot
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In-Reply-To: <174486704950.3973933.810283141514120282.stgit@mhiramat.tok.corp.google.com>
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On Thu, 17 Apr 2025 14:17:29 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -6004,6 +6004,7 @@ struct trace_mod_entry {
>  };
>  
>  struct trace_scratch {
> +	char			clock[TRACE_CLOCK_NAME_MAX];
>  	unsigned long		text_addr;
>  	unsigned long		nr_entries;
>  	struct trace_mod_entry	entries[];
> @@ -6114,6 +6115,8 @@ static void update_last_data(struct trace_array *tr)
>  	if (tr->scratch) {
>  		struct trace_scratch *tscratch = tr->scratch;
>  
> +		strscpy(tscratch->clock, trace_clocks[tr->clock_id].name,

Why copy the name and not the clock_id?

The clock ids should not change between kernels.

-- Steve

> +			TRACE_CLOCK_NAME_MAX);
>  		memset(tscratch->entries, 0,
>  		       flex_array_size(tscratch, entries, tscratch->nr_entries));
>  		tscratch->nr_entries = 0;