From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Sami Tolvanen <samitolvanen@google.com>,
Mark Rutland <mark.rutland@arm.com>,
Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
linux-kernel@vger.kernel.org,
clang-built-linux <llvm@lists.linux.dev>,
Nathan Chancellor <nathan@kernel.org>
Subject: Re: [BUG] tracing: dynamic ftrace selftest detected failures
Date: Wed, 21 Aug 2024 09:15:03 +0900 [thread overview]
Message-ID: <20240821091503.097e729cecb8560f8f51a646@kernel.org> (raw)
In-Reply-To: <20240820194914.2352a914@gandalf.local.home>
On Tue, 20 Aug 2024 19:49:14 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 21 Aug 2024 08:43:51 +0900
> Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
>
> > > Can you add the __used and see if it fixes it?
> >
> > Adding __used to DYN_FTRACE_TEST_NAME() and DYN_FTRACE_TEST_NAME2() does
> > not change, the test still fails.
>
> OK, now that sounds like a bug in LTO itself.
Hmm, I think __used just preserve the function exists as a function. But the
callsite can be optimized. This mean the __used function code is duplicated,
and embedded one copy in the callsite, but keep another copy as a function
which can be used from outside. But "noinline" attribute seems to be expected
not embedded in the callsite (because that is what "inlined" mean), so it
looks like a bug.
Thank you,
>
> -- Steve
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2024-08-21 0:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-19 8:11 [BUG] tracing: dynamic ftrace selftest detected failures Masami Hiramatsu
2024-08-19 15:29 ` Steven Rostedt
2024-08-19 15:56 ` Masami Hiramatsu
2024-08-19 16:02 ` Steven Rostedt
2024-08-19 23:34 ` Masami Hiramatsu
2024-08-20 1:03 ` Masami Hiramatsu
2024-08-20 10:48 ` Mark Rutland
2024-08-20 13:56 ` Steven Rostedt
2024-08-20 15:10 ` Sami Tolvanen
2024-08-20 15:20 ` Steven Rostedt
2024-08-20 22:05 ` Masami Hiramatsu
2024-08-20 22:11 ` Steven Rostedt
2024-08-20 23:43 ` Masami Hiramatsu
2024-08-20 23:49 ` Steven Rostedt
2024-08-21 0:15 ` Masami Hiramatsu [this message]
2024-08-21 0:21 ` Masami Hiramatsu
2024-08-21 15:06 ` Sami Tolvanen
2024-08-21 15:32 ` Mark Rutland
2024-08-21 15:42 ` Mark Rutland
2024-08-21 15:50 ` Steven Rostedt
2024-08-23 0:04 ` Masami Hiramatsu
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