Re: [linux-stable-rc:linux-5.4.y 2563/9999] arch/ia64/kernel/kprobes.c:401:24: error: implicit declaration of function '__kretprobe_trampoline_handler'; did you mean 'kretprobe_trampoline'?

[Masami Hiramatsu <mhiramat@kernel.org>]

On Thu, 13 Jan 2022 04:15:43 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Masami,
> 
> FYI, the error/warning still remains.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.4.y
> head:   0a4ce4977bbeea4560a1f32632650b388c834c8a
> commit: 77fa5e15c933a1ec812de61ad709c00aa51e96ae [2563/9999] ia64: kprobes: Use generic kretprobe trampoline handler
> config: ia64-randconfig-r002-20220112 (https://download.01.org/0day-ci/archive/20220113/202201130408.tdm9swhk-lkp@intel.com/config)
> compiler: ia64-linux-gcc (GCC) 11.2.0
> 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
>         # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=77fa5e15c933a1ec812de61ad709c00aa51e96ae
>         git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
>         git fetch --no-tags linux-stable-rc linux-5.4.y
>         git checkout 77fa5e15c933a1ec812de61ad709c00aa51e96ae
>         # save the config file to linux build tree
>         mkdir build_dir
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=ia64 SHELL=/bin/bash
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
>    arch/ia64/kernel/kprobes.c: In function 'get_kprobe_inst':
>    arch/ia64/kernel/kprobes.c:325:22: warning: variable 'template' set but not used [-Wunused-but-set-variable]
>      325 |         unsigned int template;
>          |                      ^~~~~~~~

OK, this is another issue, which is in the upstream master too.

>    arch/ia64/kernel/kprobes.c: At top level:
>    arch/ia64/kernel/kprobes.c:399:15: warning: no previous prototype for 'trampoline_probe_handler' [-Wmissing-prototypes]
>      399 | int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
>          |               ^~~~~~~~~~~~~~~~~~~~~~~~
>    arch/ia64/kernel/kprobes.c: In function 'trampoline_probe_handler':
> >> arch/ia64/kernel/kprobes.c:401:24: error: implicit declaration of function '__kretprobe_trampoline_handler'; did you mean 'kretprobe_trampoline'? [-Werror=implicit-function-declaration]
>      401 |         regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL);
>          |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>          |                        kretprobe_trampoline
>    cc1: some warnings being treated as errors

This seems that the upstream commit e792ff804f49720ce003b3e4c618b5d996256a18
has been picked to the stable-5.4.y tree accidentally.
That is a part of lockless kretprobe series and should not be picked to
the stable tree.

Greg, can you revert commit 77fa5e15c933a1ec812de61ad709c00aa51e96ae ?
(Or should I send revert patch?)

Thank you,

> 
> 
> vim +401 arch/ia64/kernel/kprobes.c
> 
>    398	
>    399	int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
>    400	{
>  > 401		regs->cr_iip = __kretprobe_trampoline_handler(regs, kretprobe_trampoline, NULL);
>    402		/*
>    403		 * By returning a non-zero value, we are telling
>    404		 * kprobe_handler() that we don't want the post_handler
>    405		 * to run (and have re-enabled preemption)
>    406		 */
>    407		return 1;
>    408	}
>    409	
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org


-- 
Masami Hiramatsu <mhiramat@kernel.org>