From: Daniel Micay <danielmicay@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>,
kbuild test robot <fengguang.wu@intel.com>
Cc: kbuild-all@01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: drivers/tty/serial/8250/8250_fintek.c:364: warning: 'probe_data' is used uninitialized in this function
Date: Wed, 09 Aug 2017 11:47:42 -0400 [thread overview]
Message-ID: <1502293662.1439.12.camel@gmail.com> (raw)
In-Reply-To: <CAK8P3a3yweXF_rXgs7ymTfeiO=bRU3gOX=zGhQcMdz4nV7sk_A@mail.gmail.com>
On Wed, 2017-08-09 at 17:32 +0200, Arnd Bergmann wrote:
> On Wed, Aug 9, 2017 at 5:07 PM, kbuild test robot
> <fengguang.wu@intel.com> wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin
> > ux.git master
> > head: bfa738cf3dfae2111626650f86135f93c5ff0a22
> > commit: 6974f0c4555e285ab217cee58b6e874f776ff409
> > include/linux/string.h: add the option of fortified string.h
> > functions
> > date: 4 weeks ago
> > config: x86_64-randconfig-v0-08092220 (attached as .config)
> > compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
> > reproduce:
> > git checkout 6974f0c4555e285ab217cee58b6e874f776ff409
> > # save the attached .config to linux build tree
> > make ARCH=x86_64
> >
> > All warnings (new ones prefixed by >>):
> >
> > In file included from include/linux/bitmap.h:8,
> > from include/linux/cpumask.h:11,
> > from arch/x86/include/asm/cpumask.h:4,
> > from arch/x86/include/asm/msr.h:10,
> > from arch/x86/include/asm/processor.h:20,
> > from arch/x86/include/asm/cpufeature.h:4,
> > from arch/x86/include/asm/thread_info.h:52,
> > from include/linux/thread_info.h:37,
> > from arch/x86/include/asm/preempt.h:6,
> > from include/linux/preempt.h:80,
> > from include/linux/spinlock.h:50,
> > from include/linux/seqlock.h:35,
> > from include/linux/time.h:5,
> > from include/linux/stat.h:18,
> > from include/linux/module.h:10,
> > from drivers/tty/serial/8250/8250_fintek.c:11:
> > include/linux/string.h: In function 'strcpy':
> > include/linux/string.h:209: warning: '______f' is static but
> > declared in inline function 'strcpy' which is not static
> > include/linux/string.h:211: warning: '______f' is static but
> > declared in inline function 'strcpy' which is not static
>
>
> This clearly comes from __trace_if() when CONFIG_PROFILE_ALL_BRANCHES
> is enabled. I did not see the warning with gcc-7.1.1, and I guess this
> only
> happens on older compilers like the gcc-4.4 that was used here.
>
> What is the reason for __FORTIFY_INLINE to be "extern __always_inline"
> rather than "static __always_inline"? If they cannot just be 'static',
> maybe
> this can be changed to depend on the compiler version.
>
> Arnd
It's important to get the semantics of using extern. It means if you do
something like &memcpy, it resolves to the address of the direct symbol
instead of generating a useless thunk for that object file. It might
also be required for Clang compatibility, I don't remember.
It could have a compiler version dependency or maybe one specifically
tied to old compiler && CONFIG_PROFILE_ALL_BRANCHES / other options that
conflict with it like that.
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WARNING: multiple messages have this Message-ID (diff)
From: Daniel Micay <danielmicay@gmail.com>
To: Arnd Bergmann <arnd@arndb.de>,
kbuild test robot <fengguang.wu@intel.com>
Cc: kbuild-all@01.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: drivers/tty/serial/8250/8250_fintek.c:364: warning: 'probe_data' is used uninitialized in this function
Date: Wed, 09 Aug 2017 11:47:42 -0400 [thread overview]
Message-ID: <1502293662.1439.12.camel@gmail.com> (raw)
In-Reply-To: <CAK8P3a3yweXF_rXgs7ymTfeiO=bRU3gOX=zGhQcMdz4nV7sk_A@mail.gmail.com>
On Wed, 2017-08-09 at 17:32 +0200, Arnd Bergmann wrote:
> On Wed, Aug 9, 2017 at 5:07 PM, kbuild test robot
> <fengguang.wu@intel.com> wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin
> > ux.git master
> > head: bfa738cf3dfae2111626650f86135f93c5ff0a22
> > commit: 6974f0c4555e285ab217cee58b6e874f776ff409
> > include/linux/string.h: add the option of fortified string.h
> > functions
> > date: 4 weeks ago
> > config: x86_64-randconfig-v0-08092220 (attached as .config)
> > compiler: gcc-4.4 (Debian 4.4.7-8) 4.4.7
> > reproduce:
> > git checkout 6974f0c4555e285ab217cee58b6e874f776ff409
> > # save the attached .config to linux build tree
> > make ARCH=x86_64
> >
> > All warnings (new ones prefixed by >>):
> >
> > In file included from include/linux/bitmap.h:8,
> > from include/linux/cpumask.h:11,
> > from arch/x86/include/asm/cpumask.h:4,
> > from arch/x86/include/asm/msr.h:10,
> > from arch/x86/include/asm/processor.h:20,
> > from arch/x86/include/asm/cpufeature.h:4,
> > from arch/x86/include/asm/thread_info.h:52,
> > from include/linux/thread_info.h:37,
> > from arch/x86/include/asm/preempt.h:6,
> > from include/linux/preempt.h:80,
> > from include/linux/spinlock.h:50,
> > from include/linux/seqlock.h:35,
> > from include/linux/time.h:5,
> > from include/linux/stat.h:18,
> > from include/linux/module.h:10,
> > from drivers/tty/serial/8250/8250_fintek.c:11:
> > include/linux/string.h: In function 'strcpy':
> > include/linux/string.h:209: warning: '______f' is static but
> > declared in inline function 'strcpy' which is not static
> > include/linux/string.h:211: warning: '______f' is static but
> > declared in inline function 'strcpy' which is not static
>
>
> This clearly comes from __trace_if() when CONFIG_PROFILE_ALL_BRANCHES
> is enabled. I did not see the warning with gcc-7.1.1, and I guess this
> only
> happens on older compilers like the gcc-4.4 that was used here.
>
> What is the reason for __FORTIFY_INLINE to be "extern __always_inline"
> rather than "static __always_inline"? If they cannot just be 'static',
> maybe
> this can be changed to depend on the compiler version.
>
> Arnd
It's important to get the semantics of using extern. It means if you do
something like &memcpy, it resolves to the address of the direct symbol
instead of generating a useless thunk for that object file. It might
also be required for Clang compatibility, I don't remember.
It could have a compiler version dependency or maybe one specifically
tied to old compiler && CONFIG_PROFILE_ALL_BRANCHES / other options that
conflict with it like that.
next prev parent reply other threads:[~2017-08-09 15:47 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-09 15:07 drivers/tty/serial/8250/8250_fintek.c:364: warning: 'probe_data' is used uninitialized in this function kbuild test robot
2017-08-09 15:32 ` Arnd Bergmann
2017-08-09 15:32 ` Arnd Bergmann
2017-08-09 15:47 ` Daniel Micay [this message]
2017-08-09 15:47 ` Daniel Micay
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