linux-kernel - Re: arch/x86/kernel/ftrace_64.o: warning: objtool: .entry.text+0x0: unreachable instruction

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Date:   Sat, 27 Jan 2018 20:21:50 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Borislav Petkov <bp@...en8.de>
Cc:     Steven Rostedt <rostedt@...dmis.org>, x86-ml <x86@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: arch/x86/kernel/ftrace_64.o: warning: objtool: .entry.text+0x0:
 unreachable instruction

On Sat, Jan 27, 2018 at 05:13:04PM +0100, Borislav Petkov wrote:
> Hey,
> 
> seen this already?
> 
> This is Linus' tree from now + tip/master also from now.

Yeah, Steven reported it a few days ago but I was in backport lala land.
It's a simple fix:

From: Josh Poimboeuf <jpoimboe@...hat.com>
Subject: [PATCH] x86/ftrace: Add one more ENDPROC annotation

When I added ORC support for the ftrace_64.S code, I missed an ENDPROC
for function_hook().  This fixes the following warning:

  arch/x86/kernel/ftrace_64.o: warning: objtool: .entry.text+0x0: unreachable instruction

Reported-by: Steven Rostedt <rostedt@...dmis.org>
Reported-by: Borislav Petkov <bp@...en8.de>
Fixes: e2ac83d74a4d ("x86/ftrace: Fix ORC unwinding from ftrace handlers")
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/kernel/ftrace_64.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index ef61f540cf0a..91b2cff4b79a 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -295,7 +295,7 @@ trace:
 	restore_mcount_regs
 
 	jmp fgraph_trace
-END(function_hook)
+ENDPROC(function_hook)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-- 
2.14.3