From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934190AbdCVLLE (ORCPT ); Wed, 22 Mar 2017 07:11:04 -0400 Received: from mail-wr0-f181.google.com ([209.85.128.181]:36847 "EHLO mail-wr0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934071AbdCVLKm (ORCPT ); Wed, 22 Mar 2017 07:10:42 -0400 From: Dmitry Vyukov To: arnd@arndb.de, akpm@linux-foundation.org Cc: Dmitry Vyukov , Mark Rutland , Andrey Ryabinin , Peter Zijlstra , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] asm-generic: fix compilation failure in cmpxchg_double() Date: Wed, 22 Mar 2017 12:10:22 +0100 Message-Id: <20170322111022.85745-1-dvyukov@google.com> X-Mailer: git-send-email 2.12.1.500.gab5fba24ee-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Arnd reported that the new code leads to compilation failures with some versions of gcc. I've filed gcc issue 72873, but we need a kernel fix as well. Remove instrumentation from cmpxchg_double() for now. Signed-off-by: Dmitry Vyukov Reported-by: Arnd Bergmann Cc: Mark Rutland Cc: Andrey Ryabinin Cc: Peter Zijlstra Cc: Will Deacon Cc: Andrey Ryabinin Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- include/asm-generic/atomic-instrumented.h | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/include/asm-generic/atomic-instrumented.h b/include/asm-generic/atomic-instrumented.h index 951bcd083925..de6c2a562a6e 100644 --- a/include/asm-generic/atomic-instrumented.h +++ b/include/asm-generic/atomic-instrumented.h @@ -229,18 +229,23 @@ INSTR_RET_BOOL2(add_negative); arch_cmpxchg64_local(____ptr, (old), (new)); \ }) +/* + * Originally we had the following code here: + * __typeof__(p1) ____p1 = (p1); + * kasan_check_write(____p1, 2 * sizeof(*____p1)); + * arch_cmpxchg_double(____p1, (p2), (o1), (o2), (n1), (n2)); + * But it leads to compilation failures (see gcc issue 72873). + * So for now it's left non-instrumented. + * There are few callers of cmpxchg_double(), so it's not critical. + */ #define cmpxchg_double(p1, p2, o1, o2, n1, n2) \ ({ \ - __typeof__(p1) ____p1 = (p1); \ - kasan_check_write(____p1, 2 * sizeof(*____p1)); \ - arch_cmpxchg_double(____p1, (p2), (o1), (o2), (n1), (n2)); \ + arch_cmpxchg_double((p1), (p2), (o1), (o2), (n1), (n2)); \ }) #define cmpxchg_double_local(p1, p2, o1, o2, n1, n2) \ ({ \ - __typeof__(p1) ____p1 = (p1); \ - kasan_check_write(____p1, 2 * sizeof(*____p1)); \ - arch_cmpxchg_double_local(____p1, (p2), (o1), (o2), (n1), (n2));\ + arch_cmpxchg_double_local((p1), (p2), (o1), (o2), (n1), (n2)); \ }) #endif /* _LINUX_ATOMIC_INSTRUMENTED_H */ -- 2.12.1.500.gab5fba24ee-goog