From: "Chen, Rong A" <rong.a.chen@intel.com>
To: Steven Rostedt <rostedt@goodmis.org>, kernel test robot <lkp@intel.com>
Cc: Ard Biesheuvel <ardb@kernel.org>,
llvm@lists.linux.dev, kbuild-all@lists.01.org,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [kbuild-all] Re: [linux-next:master 4103/11953] arch/arm/kernel/ftrace.c:229:6: warning: no previous prototype for function 'prepare_ftrace_return'
Date: Fri, 18 Mar 2022 10:24:16 +0800 [thread overview]
Message-ID: <d72b1311-2734-dca5-a105-a8ae1334627d@intel.com> (raw)
In-Reply-To: <20220310210404.7c47aa47@gandalf.local.home>
On 3/11/2022 10:04 AM, Steven Rostedt wrote:
> On Fri, 11 Mar 2022 09:44:11 +0800
> kernel test robot <lkp@intel.com> wrote:
>
>> Hi Ard,
>>
>> FYI, the error/warning still remains.
>>
>> tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
>> head: 71941773e143369a73c9c4a3b62fbb60736a1182
>> commit: 41918ec82eb6f80c8b401422f27ca76c85aa0cb7 [4103/11953] ARM: ftrace: enable the graph tracer with the EABI unwinder
>> config: arm-aspeed_g4_defconfig (https://download.01.org/0day-ci/archive/20220311/202203110903.3xDyTUVl-lkp@intel.com/config)
>> compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 276ca87382b8f16a65bddac700202924228982f6)
>> reproduce (this is a W=1 build):
>> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # install arm cross compiling tool for clang build
>> # apt-get install binutils-arm-linux-gnueabi
>> # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=41918ec82eb6f80c8b401422f27ca76c85aa0cb7
>> git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>> git fetch --no-tags linux-next master
>> git checkout 41918ec82eb6f80c8b401422f27ca76c85aa0cb7
>> # save the config file to linux build tree
>> mkdir build_dir
>> COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash arch/arm/kernel/
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> All warnings (new ones prefixed by >>):
>>
>>>> arch/arm/kernel/ftrace.c:229:6: warning: no previous prototype for function 'prepare_ftrace_return' [-Wmissing-prototypes]
>> void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
>> ^
>> arch/arm/kernel/ftrace.c:229:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
>> void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
>> ^
>> static
>> 1 warning generated.
>>
>
> Hmm, this is only called from assembly code, which doesn't care about
> prototypes. Is there a way to quiet this warning to say "this is called
> only by assembly"?
>
> Or do we just add a useless prototype to shut it up?
>
> -- Steve
Hi Steve,
Sorry for the inconvenience, it's a duplicate false positive:
https://lore.kernel.org/linux-mm/2db6ea89-846a-8d4e-a5c3-954411332029@intel.com/
please ignore the report, we are still working on it.
Best Regards,
Rong Chen
>
>
>>
>> vim +/prepare_ftrace_return +229 arch/arm/kernel/ftrace.c
>>
>> 376cfa8730c08c Tim Bird 2010-10-09 226
>> 376cfa8730c08c Tim Bird 2010-10-09 227 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 228 asmlinkage
>> 376cfa8730c08c Tim Bird 2010-10-09 @229 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 230 unsigned long frame_pointer,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 231 unsigned long stack_pointer)
>> 376cfa8730c08c Tim Bird 2010-10-09 232 {
>> 376cfa8730c08c Tim Bird 2010-10-09 233 unsigned long return_hooker = (unsigned long) &return_to_handler;
>> 376cfa8730c08c Tim Bird 2010-10-09 234 unsigned long old;
>> 376cfa8730c08c Tim Bird 2010-10-09 235
>> 376cfa8730c08c Tim Bird 2010-10-09 236 if (unlikely(atomic_read(¤t->tracing_graph_pause)))
>> 376cfa8730c08c Tim Bird 2010-10-09 237 return;
>> 376cfa8730c08c Tim Bird 2010-10-09 238
>> 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 239 if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER)) {
>> 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 240 /* FP points one word below parent's top of stack */
>> 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 241 frame_pointer += 4;
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 242 } else {
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 243 struct stackframe frame = {
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 244 .fp = frame_pointer,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 245 .sp = stack_pointer,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 246 .lr = self_addr,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 247 .pc = self_addr,
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 248 };
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 249 if (unwind_frame(&frame) < 0)
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 250 return;
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 251 if (frame.lr != self_addr)
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 252 parent = frame.lr_addr;
>> 41918ec82eb6f8 Ard Biesheuvel 2022-01-25 253 frame_pointer = frame.sp;
>> 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 254 }
>> 953f534a7ed6b7 Ard Biesheuvel 2022-01-25 255
>> 376cfa8730c08c Tim Bird 2010-10-09 256 old = *parent;
>> 376cfa8730c08c Tim Bird 2010-10-09 257 *parent = return_hooker;
>> 376cfa8730c08c Tim Bird 2010-10-09 258
>> f1f5b14afd7cce Steven Rostedt (VMware 2018-11-18 259) if (function_graph_enter(old, self_addr, frame_pointer, NULL))
>> 376cfa8730c08c Tim Bird 2010-10-09 260 *parent = old;
>> 376cfa8730c08c Tim Bird 2010-10-09 261 }
>> dd686eb13959e4 Rabin Vincent 2010-11-06 262
>>
>> :::::: The code at line 229 was first introduced by commit
>> :::::: 376cfa8730c08c0394d0aa1d4a80fd8c9971f323 ARM: ftrace: function graph tracer support
>>
>> :::::: TO: Tim Bird <tim.bird@am.sony.com>
>> :::::: CC: Rabin Vincent <rabin@rab.in>
>>
>> ---
>> 0-DAY CI Kernel Test Service
>> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> _______________________________________________
> kbuild-all mailing list -- kbuild-all@lists.01.org
> To unsubscribe send an email to kbuild-all-leave@lists.01.org
>
next prev parent reply other threads:[~2022-03-18 2:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-11 1:44 [linux-next:master 4103/11953] arch/arm/kernel/ftrace.c:229:6: warning: no previous prototype for function 'prepare_ftrace_return' kernel test robot
2022-03-11 2:04 ` Steven Rostedt
2022-03-11 2:04 ` Steven Rostedt
2022-03-18 2:24 ` Chen, Rong A [this message]
2022-03-18 18:26 ` Nick Desaulniers
2022-03-18 18:26 ` Nick Desaulniers
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