Re: [sj:damon/next 30/144] mm/damon/core.c:1693:25: warning: zero-length gnu_printf format string

Re: [sj:damon/next 30/144] mm/damon/core.c:1693:25: warning: zero-length gnu_printf format string

[SeongJae Park]

On Sun, 22 Feb 2026 13:48:19 +0800 kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git damon/next
> head:   4ac50a8b182685ab2e9f2ff9411ce5c0ef3af0ac
> commit: ebbed03fc342824e63925232c8dc4ea55e54e2a3 [30/144] mm/damon/core: add damon_reset_aggregated() debug_sanity check
> config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20260222/202602221352.odZW8x1R-lkp@intel.com/config)
> compiler: m68k-linux-gcc (GCC) 15.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260222/202602221352.odZW8x1R-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/202602221352.odZW8x1R-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from arch/m68k/include/asm/bug.h:32,
>                     from include/linux/bug.h:5,
>                     from include/linux/thread_info.h:13,
>                     from include/asm-generic/preempt.h:5,
>                     from ./arch/m68k/include/generated/asm/preempt.h:1,
>                     from include/linux/preempt.h:79,
>                     from arch/m68k/include/asm/processor.h:11,
>                     from include/linux/sched.h:13,
>                     from include/linux/cgroup.h:12,
>                     from include/linux/memcontrol.h:13,
>                     from include/linux/damon.h:11,
>                     from mm/damon/core.c:10:
>    mm/damon/core.c: In function 'damon_verify_reset_aggregated':
> >> mm/damon/core.c:1693:25: warning: zero-length gnu_printf format string [-Wformat-zero-length]
>     1693 |         WARN_ONCE(true, "");
>          |                         ^~
>    include/asm-generic/bug.h:142:62: note: in definition of macro '__WARN_printf'
>      142 |                 warn_slowpath_fmt(__FILE__, __LINE__, taint, arg);      \
>          |                                                              ^~~
>    include/linux/once_lite.h:31:25: note: in expansion of macro 'WARN'
>       31 |                         func(__VA_ARGS__);                              \
>          |                         ^~~~
>    include/asm-generic/bug.h:185:9: note: in expansion of macro 'DO_ONCE_LITE_IF'
>      185 |         DO_ONCE_LITE_IF(condition, WARN, 1, format)
>          |         ^~~~~~~~~~~~~~~
>    mm/damon/core.c:1693:9: note: in expansion of macro 'WARN_ONCE'
>     1693 |         WARN_ONCE(true, "");
>          |         ^~~~~~~~~

Thank you for this report!  I just pushed a fix to damon/next.


Thanks,
SJ

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