From: Nathan Chancellor <natechancellor@gmail.com> To: Nick Desaulniers <ndesaulniers@google.com> Cc: akpm@linux-foundation.org, 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 Subject: Re: [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_ Date: Mon, 30 Jul 2018 16:25:12 -0700 [thread overview] Message-ID: <20180730232512.GA1688@flashbox> (raw) In-Reply-To: <20180730213412.242849-3-ndesaulniers@google.com> On Mon, Jul 30, 2018 at 02:34:12PM -0700, Nick Desaulniers wrote: > 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> Tested-and-reviewed-by: Nathan Chancellor <natechancellor@gmail.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 >
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <natechancellor@gmail.com> To: Nick Desaulniers <ndesaulniers@google.com> Cc: akpm@linux-foundation.org, 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 Subject: Re: [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_ Date: Mon, 30 Jul 2018 16:25:12 -0700 [thread overview] Message-ID: <20180730232512.GA1688@flashbox> (raw) In-Reply-To: <20180730213412.242849-3-ndesaulniers@google.com> On Mon, Jul 30, 2018 at 02:34:12PM -0700, Nick Desaulniers wrote: > 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'�tre: 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> Tested-and-reviewed-by: Nathan Chancellor <natechancellor@gmail.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 23:25 UTC|newest] Thread overview: 17+ 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 ` [PATCH v2 2/2] kernel.h: Disable -Wreturn-stack-address for _THIS_IP_ Nick Desaulniers 2018-07-30 23:25 ` Nathan Chancellor [this message] 2018-07-30 23:25 ` 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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