Re: arch/powerpc/kernel/optprobes.c:34:1: error: unused function 'is_kprobe_ppc_optinsn_slot'

[Nathan Chancellor]

On 5/11/2021 9:47 AM, Christophe Leroy wrote:
> Hi All,
>
> Le 11/05/2021 à 18:30, kernel test robot a écrit :
> > Hi Christophe,
> >
> > First bad commit (maybe != root cause):
> >
> > tree:   
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   1140ab592e2ebf8153d2b322604031a8868ce7a5
> > commit: eacf4c0202654adfa94bbb17b5c5c77c0be14af8 powerpc: Enable 
> > OPTPROBES on PPC32
> > date:   3 weeks ago
> > config: powerpc-randconfig-r033-20210511 (attached as .config)
> > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 
> > a0fed635fe1701470062495a6ffee1c608f3f1bc)
>
> A clang issue ?
>
>
> > 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 powerpc cross compiling tool for clang build
> >          # apt-get install binutils-powerpc-linux-gnu
> >          # 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=eacf4c0202654adfa94bbb17b5c5c77c0be14af8 
> >
> >          git remote add linus 
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >          git fetch --no-tags linus master
> >          git checkout eacf4c0202654adfa94bbb17b5c5c77c0be14af8
> >          # save the attached .config to linux build tree
> >          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross 
> > W=1 ARCH=powerpc
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> >
> > All errors (new ones prefixed by >>):
> >
> > > > arch/powerpc/kernel/optprobes.c:34:1: error: unused function 
> > > > 'is_kprobe_ppc_optinsn_slot' [-Werror,-Wunused-function]
> >     DEFINE_INSN_CACHE_OPS(ppc_optinsn);
> >     ^
> >     include/linux/kprobes.h:306:20: note: expanded from macro 
> > 'DEFINE_INSN_CACHE_OPS'
> >     static inline bool is_kprobe_##__name##_slot(unsigned long 
> > addr)        \
>
> That's a 'static inline', shouldn't generate an 'unused function' warning.
This is a W=1 build, which means that "inline" does not silence unused 
function warnings with clang because of commit 6863f5643dd7 ("kbuild: 
allow Clang to find unused static inline functions for W=1 build").

Cheers,
Nathan

> >                        ^
> >     <scratch space>:16:1: note: expanded from here
> >     is_kprobe_ppc_optinsn_slot
> >     ^
> >     1 error generated.
> >
> >
> > vim +/is_kprobe_ppc_optinsn_slot +34 arch/powerpc/kernel/optprobes.c
> >
> > 51c9c084399352 Anju T 2017-02-08  20
> > 51c9c084399352 Anju T 2017-02-08  21  #define TMPL_CALL_HDLR_IDX    \
> > 51c9c084399352 Anju T 2017-02-08  22      
> > (optprobe_template_call_handler - optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  23  #define TMPL_EMULATE_IDX    \
> > 51c9c084399352 Anju T 2017-02-08  24      
> > (optprobe_template_call_emulate - optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  25  #define TMPL_RET_IDX        \
> > 51c9c084399352 Anju T 2017-02-08  26      (optprobe_template_ret - 
> > optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  27  #define TMPL_OP_IDX        \
> > 51c9c084399352 Anju T 2017-02-08  28      
> > (optprobe_template_op_address - optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  29  #define TMPL_INSN_IDX        \
> > 51c9c084399352 Anju T 2017-02-08  30      (optprobe_template_insn - 
> > optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  31  #define TMPL_END_IDX        \
> > 51c9c084399352 Anju T 2017-02-08  32      (optprobe_template_end - 
> > optprobe_template_entry)
> > 51c9c084399352 Anju T 2017-02-08  33
> > 51c9c084399352 Anju T 2017-02-08 @34  DEFINE_INSN_CACHE_OPS(ppc_optinsn);
> > 51c9c084399352 Anju T 2017-02-08  35
> >
> > :::::: The code at line 34 was first introduced by commit
> > :::::: 51c9c0843993528bffc920c54c2121d9e6f8b090 powerpc/kprobes: 
> > Implement Optprobes
> >
> > :::::: TO: Anju T <anju@xxxxxxxxxxxxxxxxxx>
> > :::::: CC: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
> >
> > ---
> > 0-DAY CI Kernel Test Service, Intel Corporation
> > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx