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From: Marco Elver <elver@google.com>
To: elver@google.com
Cc: paulmck@kernel.org, dvyukov@google.com, glider@google.com,
	andreyknvl@google.com, kasan-dev@googlegroups.com,
	linux-kernel@vger.kernel.org, tglx@linutronix.de,
	mingo@kernel.org, peterz@infradead.org, will@kernel.org,
	clang-built-linux@googlegroups.com, bp@alien8.de
Subject: [PATCH -tip v3 09/11] data_race: Avoid nested statement expression
Date: Thu, 21 May 2020 16:20:45 +0200	[thread overview]
Message-ID: <20200521142047.169334-10-elver@google.com> (raw)
In-Reply-To: <20200521142047.169334-1-elver@google.com>

It appears that compilers have trouble with nested statement
expressions. Therefore remove one level of statement expression nesting
from the data_race() macro. This will help us avoid potential problems
in future as its usage increases.

Link: https://lkml.kernel.org/r/20200520221712.GA21166@zn.tnic
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
---
v3:
* Fix for 'const' non-scalar expressions.
v2:
* Add patch to series in response to above linked discussion.
---
 include/linux/compiler.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 7444f026eead..379a5077e9c6 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -211,12 +211,12 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  */
 #define data_race(expr)							\
 ({									\
-	__kcsan_disable_current();					\
-	({								\
-		__unqual_scalar_typeof(({ expr; })) __v = ({ expr; });	\
-		__kcsan_enable_current();				\
-		__v;							\
+	__unqual_scalar_typeof(({ expr; })) __v = ({			\
+		__kcsan_disable_current();				\
+		expr;							\
 	});								\
+	__kcsan_enable_current();					\
+	__v;								\
 })
 
 /*
-- 
2.26.2.761.g0e0b3e54be-goog


  parent reply	other threads:[~2020-05-21 14:23 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-21 14:20 [PATCH -tip v3 00/11] Fix KCSAN for new ONCE (require Clang 11) Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 01/11] ubsan, kcsan: don't combine sanitizer with kcov on clang Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 02/11] kcsan: Avoid inserting __tsan_func_entry/exit if possible Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 03/11] kcsan: Support distinguishing volatile accesses Marco Elver
2020-05-22 10:26   ` Borislav Petkov
2020-05-22 10:34     ` Marco Elver
2020-05-22 10:47       ` Borislav Petkov
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 04/11] kcsan: Pass option tsan-instrument-read-before-write to Clang Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 05/11] kcsan: Remove 'noinline' from __no_kcsan_or_inline Marco Elver
2020-05-29 17:07   ` Peter Zijlstra
2020-05-29 18:36     ` Marco Elver
2020-05-29 18:59       ` Peter Zijlstra
2020-05-21 14:20 ` [PATCH -tip v3 06/11] kcsan: Restrict supported compilers Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 07/11] kcsan: Update Documentation to change " Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 08/11] READ_ONCE, WRITE_ONCE: Remove data_race() and unnecessary checks Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE() tip-bot2 for Marco Elver
2020-05-21 14:20 ` Marco Elver [this message]
2020-05-21 20:21   ` [PATCH -tip v3 09/11] data_race: Avoid nested statement expression Nick Desaulniers
2020-05-26 10:42     ` Arnd Bergmann
2020-05-26 12:02       ` Will Deacon
2020-05-26 12:19         ` Arnd Bergmann
2020-05-26 13:12           ` Marco Elver
2020-05-26 17:33             ` Marco Elver
2020-05-26 19:00               ` Arnd Bergmann
2020-05-26 23:10                 ` Arnd Bergmann
2020-05-27  7:22                   ` Will Deacon
2020-05-27  7:44                     ` Marco Elver
2020-05-27  9:26                       ` Arnd Bergmann
2020-05-28 12:53                         ` Stephen Rothwell
2020-05-26 21:36               ` Peter Zijlstra
2020-05-21 14:20 ` [PATCH -tip v3 10/11] compiler.h: Move function attributes to compiler_types.h Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-21 14:20 ` [PATCH -tip v3 11/11] compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining Marco Elver
2020-05-22 16:08   ` [tip: locking/kcsan] " tip-bot2 for Marco Elver
2020-05-22 11:35 ` [PATCH -tip v3 00/11] Fix KCSAN for new ONCE (require Clang 11) Peter Zijlstra

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