From: Nick Desaulniers <ndesaulniers@google.com>
To: akpm@linux-foundation.org, natechancellor@gmail.com
Cc: arnd@arndb.de, paul.burton@mips.com, christophe.leroy@c-s.fr,
shorne@gmail.com, yamada.masahiro@socionext.com,
keescook@chromium.org, mingo@kernel.org,
gregkh@linuxfoundation.org, tglx@linutronix.de,
rdunlap@infradead.org, bp@suse.de, neilb@suse.com,
linux-kernel@vger.kernel.org, aryabinin@virtuozzo.com,
dwmw@amazon.co.uk, sandipan@linux.vnet.ibm.com,
linux@rasmusvillemoes.dk, paullawrence@google.com,
andreyknvl@google.com, will.deacon@arm.com,
ghackmann@android.com, stable@vger.kernel.org,
ghackmann@google.com, mka@chromium.org, jpoimboe@redhat.com,
wvw@google.com, avagin@openvz.org,
Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_
Date: Mon, 30 Jul 2018 14:34:12 -0700 [thread overview]
Message-ID: <20180730213412.242849-3-ndesaulniers@google.com> (raw)
In-Reply-To: <20180730213412.242849-1-ndesaulniers@google.com>
Starting with Clang-7.0, _THIS_IP_ generates -Wreturn-stack-address
warnings for almost every translation unit. In general, I'd prefer to
leave this on (returning the address of a stack allocated variable is in
general a bad idea) and disable it only at whitelisted call sites.
We can't do something like:
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wreturn-stack-address"
<code>
#pragma clang diagnostic pop
in a GNU Statement Expression or macro, hence we use _Pragma, which is
its raison d'être: https://gcc.gnu.org/onlinedocs/cpp/Pragmas.html
We also can't use compiler specific pragma's without triggering
-Werror=unknown-pragmas in other compilers, so use __diag.
Cc: stable@vger.kernel.org # 4.17, 4.14, 4.9, 4.4
Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
include/linux/kernel.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 941dc0a5a877..909bb771c0ca 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -168,7 +168,15 @@
#define _RET_IP_ (unsigned long)__builtin_return_address(0)
-#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
+#define _THIS_IP_ ( \
+{ \
+ __label__ __here; \
+ __diag_push() \
+ __diag_ignore(CLANG, 7, "-Wreturn-stack-address", "") \
+__here: (unsigned long)&&__here; \
+ __diag_pop() \
+} \
+)
#ifdef CONFIG_LBDAF
# include <asm/div64.h>
--
2.18.0.345.g5c9ce644c3-goog
next prev parent reply other threads:[~2018-07-30 21:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-30 21:34 [PATCH v2 0/2] CLANG_VERSION and __diag macros Nick Desaulniers
2018-07-30 21:34 ` [PATCH v2 1/2] compiler-clang.h: Add " Nick Desaulniers
2018-07-30 23:25 ` Nathan Chancellor
2018-08-31 21:50 ` Nick Desaulniers
2018-08-31 22:16 ` Miguel Ojeda
2018-07-30 21:34 ` Nick Desaulniers [this message]
2018-07-30 23:25 ` [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_ Nathan Chancellor
2018-07-31 10:27 ` kbuild test robot
2018-07-31 16:48 ` Nick Desaulniers
2018-07-31 17:02 ` Kees Cook
2018-07-31 17:09 ` Nick Desaulniers
2018-07-31 18:58 ` Nick Desaulniers
2018-07-31 21:10 ` Nick Desaulniers
2018-07-31 17:02 ` Nathan Chancellor
2018-07-31 13:53 ` kbuild test robot
2018-07-31 16:55 ` Nick Desaulniers
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