From: kernel test robot <lkp@intel.com>
To: Zhan Xusheng <zhanxusheng1024@gmail.com>
Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
x86@kernel.org, "Thomas Gleixner" <tglx@kernel.org>,
"Thomas Weißschuh " <thomas.weissschuh@linutronix.de>
Subject: [tip:timers/vdso 1/4] include/vdso/math64.h:14:17: error: implicit declaration of function 'OPTIMIZER_HIDE_VAR'
Date: Wed, 30 Sep 2026 13:13:06 +0800 [thread overview]
Message-ID: <202609301300.uAawkHuh-lkp@intel.com> (raw)
tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso
head: ca46a07c4b68246c4e400ce3649ab7228a878d8f
commit: 37db375ad90467d7e3ce4e450b3d1c4f297d4ed3 [1/4] vdso/math64: Use OPTIMIZER_HIDE_VAR() in __iter_div_u64_rem()
config: m68k-atari_defconfig (https://download.01.org/0day-ci/archive/20260930/202609301300.uAawkHuh-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 16.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260930/202609301300.uAawkHuh-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/202609301300.uAawkHuh-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/math64.h:8,
from include/linux/time.h:6,
from include/linux/stat.h:19,
from include/linux/fs_dirent.h:5,
from include/linux/fs/super_types.h:5,
from include/linux/fs/super.h:5,
from include/linux/fs.h:5,
from include/linux/highmem.h:5,
from include/linux/bvec.h:10,
from include/linux/blk_types.h:10,
from include/linux/blkdev.h:9,
from drivers/md/md-linear.c:7:
include/vdso/math64.h: In function '__iter_div_u64_rem':
>> include/vdso/math64.h:14:17: error: implicit declaration of function 'OPTIMIZER_HIDE_VAR' [-Wimplicit-function-declaration]
14 | OPTIMIZER_HIDE_VAR(dividend);
| ^~~~~~~~~~~~~~~~~~
--
In file included from include/linux/math64.h:8,
from include/linux/time.h:6,
from include/linux/stat.h:19,
from include/linux/fs_dirent.h:5,
from include/linux/fs/super_types.h:5,
from include/linux/fs/super.h:5,
from include/linux/fs.h:5,
from include/linux/highmem.h:5,
from include/linux/bvec.h:10,
from include/linux/blk_types.h:10,
from include/linux/blkdev.h:9,
from drivers/md/raid5.c:38:
include/vdso/math64.h: In function '__iter_div_u64_rem':
>> include/vdso/math64.h:14:17: error: implicit declaration of function 'OPTIMIZER_HIDE_VAR' [-Wimplicit-function-declaration]
14 | OPTIMIZER_HIDE_VAR(dividend);
| ^~~~~~~~~~~~~~~~~~
drivers/md/raid5.c: In function 'handle_stripe_dirtying':
drivers/md/raid5.c:4306:21: warning: variable 'qread' set but not used [-Wunused-but-set-variable=]
4306 | int qread =0;
| ^~~~~
--
In file included from include/linux/math64.h:8,
from include/linux/time.h:6,
from include/linux/stat.h:19,
from include/linux/fs_dirent.h:5,
from include/linux/fs/super_types.h:5,
from include/linux/fs/super.h:5,
from include/linux/fs.h:5,
from include/linux/highmem.h:5,
from include/linux/bvec.h:10,
from include/linux/blk_types.h:10,
from include/linux/blkdev.h:9,
from raid5.c:38:
include/vdso/math64.h: In function '__iter_div_u64_rem':
>> include/vdso/math64.h:14:17: error: implicit declaration of function 'OPTIMIZER_HIDE_VAR' [-Wimplicit-function-declaration]
14 | OPTIMIZER_HIDE_VAR(dividend);
| ^~~~~~~~~~~~~~~~~~
raid5.c: In function 'handle_stripe_dirtying':
raid5.c:4306:21: warning: variable 'qread' set but not used [-Wunused-but-set-variable=]
4306 | int qread =0;
| ^~~~~
vim +/OPTIMIZER_HIDE_VAR +14 include/vdso/math64.h
4
5 static __always_inline u32 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
6 {
7 u32 ret = 0;
8
9 while (dividend >= divisor) {
10 /*
11 * Prevent the compiler from optimising this loop into a
12 * modulo operation.
13 */
> 14 OPTIMIZER_HIDE_VAR(dividend);
15
16 dividend -= divisor;
17 ret++;
18 }
19
20 *remainder = dividend;
21
22 return ret;
23 }
24
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
reply other threads:[~2026-09-30 5:13 UTC|newest]
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