[tip:core/urgent] objtool: Enclose contents of unreachable() macro in a block

[tip-bot for Josh Poimboeuf <tipbot@zytor.com>]

Commit-ID:  4e4636cf981b5b629fbfb78aa9f232e015f7d521
Gitweb:     http://git.kernel.org/tip/4e4636cf981b5b629fbfb78aa9f232e015f7d521
Author:     Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Mon, 27 Feb 2017 22:21:16 -0600
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 28 Feb 2017 07:47:26 +0100

objtool: Enclose contents of unreachable() macro in a block

Guenter Roeck reported a boot failure in mips64.  It was bisected to the
following commit:

  d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends")

The unreachable() macro was formerly only composed of a single
statement.  The above commit added a second statement, but neglected to
enclose the statements in a block.

Suggested-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends")
Link: http://lkml.kernel.org/r/20170228042116.glmwmwiohcix7o4a@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/linux/compiler-gcc.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index de47134..f457b52 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -215,7 +215,8 @@
  * this in the preprocessor, but we can live with this because they're
  * unreleased.  Really, we need to have autoconf for the kernel.
  */
-#define unreachable() annotate_unreachable(); __builtin_unreachable()
+#define unreachable() \
+	do { annotate_unreachable(); __builtin_unreachable(); } while (0)
 
 /* Mark a function definition as prohibited from being cloned. */
 #define __noclone	__attribute__((__noclone__, __optimize__("no-tracer")))