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Date: Wed, 3 Apr 2024 09:53:55 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>, Andrii Nakryiko
 <andrii@kernel.org>, linux-trace-kernel@vger.kernel.org,
 bpf@vger.kernel.org, jolsa@kernel.org, "Paul E . McKenney"
 <paulmck@kernel.org>, Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] ftrace: make extra rcu_is_watching() validation check
 optional
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On Tue, 2 Apr 2024 21:00:19 -0700
Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:

> I just noticed another rcu_is_watching() call, in rethook_try_get(),
> which seems to be a similar and complementary validation check to the
> one we are putting under CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING option
> in this patch. It feels like both of them should be controlled by the
> same settings. WDYT? Can I add CONFIG_FTRACE_VALIDATE_RCU_IS_WATCHING
> guard around rcu_is_watching() check in rethook_try_get() as well?

That is totally up to Masami. It may have even less overhead as I'm not
sure how many times that gets called, and there may be more work to do than
with function tracing.

-- Steve