linux-kernel - [PATCH 2/2] x86/unwind/orc: Silence warnings caused by missing ORC data

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Message-Id: <06d02c4bbb220bd31668db579278b0352538efbb.1612534649.git.jpoimboe@redhat.com>
Date:   Fri,  5 Feb 2021 08:24:03 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Ivan Babrou <ivan@...udflare.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH 2/2] x86/unwind/orc: Silence warnings caused by missing ORC data

The ORC unwinder attempts to fall back to frame pointers when ORC data
is missing for a given instruction.  It sets state->error, but then
tries to keep going as a best-effort type of thing.  That may result in
further warnings if the unwinder gets lost.

Until we have some way to register generated code with the unwinder,
missing ORC will be expected, and occasionally going off the rails will
also be expected.  So don't warn about it.

Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
---
 arch/x86/kernel/unwind_orc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index c451d5f6422f..027b72b5c9ed 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -13,7 +13,7 @@

 #define orc_warn_current(args...)					\
 ({									\
-	if (state->task == current)					\
+	if (state->task == current && !state->error)			\
 		orc_warn(args);						\
 })

-- 
2.29.2