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

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Message-ID: <161503313330.398.3537176169423600436.tip-bot2@tip-bot2>
Date:   Sat, 06 Mar 2021 12:18:53 -0000
From:   "tip-bot2 for Josh Poimboeuf" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>,
        Ivan Babrou <ivan@...udflare.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: x86/urgent] x86/unwind/orc: Silence warnings caused by missing ORC data

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     b59cc97674c947861783ca92b9a6e7d043adba96
Gitweb:        https://git.kernel.org/tip/b59cc97674c947861783ca92b9a6e7d043adba96
Author:        Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate:    Fri, 05 Feb 2021 08:24:03 -06:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Sat, 06 Mar 2021 13:09:45 +01:00

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Tested-by: Ivan Babrou <ivan@...udflare.com>
Link: https://lkml.kernel.org/r/06d02c4bbb220bd31668db579278b0352538efbb.1612534649.git.jpoimboe@redhat.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 1bcc14c..a120253 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);						\
 })