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Date:   Wed, 30 Mar 2022 12:54:13 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     rostedt <rostedt@goodmis.org>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>,
        Beau Belgrave <beaub@linux.microsoft.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-trace-devel <linux-trace-devel@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, netdev <netdev@vger.kernel.org>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Message-ID: <1546405229.199729.1648659253425.JavaMail.zimbra@efficios.com>
In-Reply-To: <20220329222514.51af6c07@gandalf.local.home>
References: <20220329222514.51af6c07@gandalf.local.home>
Subject: Re: [PATCH] tracing: Set user_events to BROKEN
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Thread-Topic: tracing: Set user_events to BROKEN
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----- On Mar 29, 2022, at 10:25 PM, rostedt rostedt@goodmis.org wrote:

> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
> 
> After being merged, user_events become more visible to a wider audience
> that have concerns with the current API. It is too late to fix this for
> this release, but instead of a full revert, just mark it as BROKEN (which
> prevents it from being selected in make config). Then we can work finding
> a better API. If that fails, then it will need to be completely reverted.

Hi Steven,

What are the constraints for changing a uapi header after it has been present
in a kernel release ?

If we are not ready to commit to an ABI, perhaps it would be safer to ensure
that include/uapi/linux/user_events.h is not installed with the uapi headers
until it's ready.

Thanks,

Mathieu

> 
> Link:
> https://lore.kernel.org/all/2059213643.196683.1648499088753.JavaMail.zimbra@efficios.com/
> 
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> kernel/trace/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
> 
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 16a52a71732d..edc8159f63ef 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -741,6 +741,7 @@ config USER_EVENTS
> 	bool "User trace events"
> 	select TRACING
> 	select DYNAMIC_EVENTS
> +	depends on BROKEN # API needs to be straighten out
> 	help
> 	  User trace events are user-defined trace events that
> 	  can be used like an existing kernel trace event.  User trace
> --
> 2.35.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com