Commit-ID:  2b5db66862b95532cb6cca8165ae6eb73633cf85
Gitweb:     https://git.kernel.org/tip/2b5db66862b95532cb6cca8165ae6eb73633cf85
Author:     Josh Poimboeuf <jpoim...@redhat.com>
AuthorDate: Thu, 8 Feb 2018 17:09:26 -0600
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Thu, 15 Feb 2018 01:15:49 +0100

x86/debug, objtool: Annotate WARN()-related UD2 as reachable

By default, objtool assumes that a UD2 is a dead end.  This is mainly
because GCC 7+ sometimes inserts a UD2 when it detects a divide-by-zero
condition.

Now that WARN() is moving back to UD2, annotate the code after it as
reachable so objtool can follow the code flow.

Reported-by: Borislav Petkov <b...@alien8.de>
Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Arjan van de Ven <ar...@linux.intel.com>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: kbuild test robot <fengguang...@intel.com>
Link: 
http://lkml.kernel.org/r/0e483379275a42626ba8898117f918e1bf661e40.1518130694.git.jpoim...@redhat.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/include/asm/bug.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index 34d99af4..71e6f4bf 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -77,7 +77,11 @@ do {                                                         
\
        unreachable();                                          \
 } while (0)
 
-#define __WARN_FLAGS(flags)    _BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags))
+#define __WARN_FLAGS(flags)                                    \
+do {                                                           \
+       _BUG_FLAGS(ASM_UD0, BUGFLAG_WARNING|(flags));           \
+       annotate_reachable();                                   \
+} while (0)
 
 #include <asm-generic/bug.h>
 

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