tree: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-5.13.y-rt-testing head: ef625e4b904469d3c5d6962b36abaed37f49db62 commit: 4d507329b3b9318f8fddbc1508ce38d324b3325a [204/232] x86: Enable RT also on 32bit config: i386-randconfig-r005-20210806 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/commit/?id=4d507329b3b9318f8fddbc1508ce38d324b3325a git remote add linux-rt-devel https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git git fetch --no-tags linux-rt-devel linux-5.13.y-rt-testing git checkout 4d507329b3b9318f8fddbc1508ce38d324b3325a # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> kernel/locking/spinlock_rt.c:244:13: warning: no previous prototype for 'rt_rwlock_is_contended' [-Wmissing-prototypes] 244 | int __sched rt_rwlock_is_contended(rwlock_t *rwlock) | ^~~~~~~~~~~~~~~~~~~~~~ vim +/rt_rwlock_is_contended +244 kernel/locking/spinlock_rt.c 387b12793ce0fa Thomas Gleixner 2021-07-06 243 387b12793ce0fa Thomas Gleixner 2021-07-06 @244 int __sched rt_rwlock_is_contended(rwlock_t *rwlock) 387b12793ce0fa Thomas Gleixner 2021-07-06 245 { 387b12793ce0fa Thomas Gleixner 2021-07-06 246 return rw_base_is_contended(&rwlock->rwbase); 387b12793ce0fa Thomas Gleixner 2021-07-06 247 } 387b12793ce0fa Thomas Gleixner 2021-07-06 248 EXPORT_SYMBOL(rt_rwlock_is_contended); 387b12793ce0fa Thomas Gleixner 2021-07-06 249 :::::: The code at line 244 was first introduced by commit :::::: 387b12793ce0faedbfc4563aaf557f664c95f1a9 locking/rwlock: Provide RT variant :::::: TO: Thomas Gleixner :::::: CC: Thomas Gleixner --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org