Re: [PATCH v5 1/3] ring-buffer: Flush and stop persistent ring buffer on panic

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Fri, 27 Feb 2026 02:48:26 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Masami,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v7.0-rc1 next-20260226]
> [cannot apply to trace/for-next]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Masami-Hiramatsu-Google/ring-buffer-Flush-and-stop-persistent-ring-buffer-on-panic/20260226-222418
> base:   linus/master
> patch link:    https://lore.kernel.org/r/177211311593.419230.2212568977306190482.stgit%40mhiramat.tok.corp.google.com
> patch subject: [PATCH v5 1/3] ring-buffer: Flush and stop persistent ring buffer on panic
> config: sparc-randconfig-001-20260227 (https://download.01.org/0day-ci/archive/20260227/202602270244.3JWhusi4-lkp@intel.com/config)
> compiler: sparc64-linux-gcc (GCC) 11.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260227/202602270244.3JWhusi4-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202602270244.3JWhusi4-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    kernel/trace/ring_buffer.c: In function 'rb_flush_buffer_cb':
> >> kernel/trace/ring_buffer.c:2481:9: error: implicit declaration of function 'flush_cache_all'; did you mean 'flush_cache_page'? [-Werror=implicit-function-declaration]
>     2481 |         flush_cache_all();
>          |         ^~~~~~~~~~~~~~~
>          |         flush_cache_page
>    cc1: some warnings being treated as errors

I guess this is a miss of the sparc. Anyway, I will add asm/ring_buffer.h
to define a wrapper macro. At least I need to sync the cache on arm64 but
flush_cache_all() is a dummy on arm64. I would like to use dcache_clear_pop()
instead.

Thanks,

> 
> 
> vim +2481 kernel/trace/ring_buffer.c
> 
>   2475	
>   2476	static int rb_flush_buffer_cb(struct notifier_block *nb, unsigned long event, void *data)
>   2477	{
>   2478		struct trace_buffer *buffer = container_of(nb, struct trace_buffer, flush_nb);
>   2479	
>   2480		ring_buffer_record_off(buffer);
> > 2481		flush_cache_all();
>   2482		return NOTIFY_DONE;
>   2483	}
>   2484	
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>