Hi Andrii, I love your patch! Yet something to improve: [auto build test ERROR on bpf-next/master] [also build test ERROR on next-20200512] [cannot apply to bpf/master rcu/dev v5.7-rc5] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/BPF-ring-buffer/... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: sh-allmodconfig (attached as .config) compiler: sh4-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=sh If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All error/warnings (new ones prefixed by >>): In file included from include/linux/kernel.h:11, from include/linux/list.h:9, from include/linux/timer.h:5, from include/linux/workqueue.h:9, from include/linux/bpf.h:9, from kernel/bpf/ringbuf.c:1: kernel/bpf/ringbuf.c: In function 'bpf_ringbuf_commit': 350 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^ include/linux/compiler.h:331:4: note: in definition of macro '__compiletime_assert' 331 | prefix ## suffix(); | ^~~~~~ include/linux/compiler.h:350:2: note: in expansion of macro '_compiletime_assert' 350 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) | ^~~~~~~~~~~~~~~~~~~ include/linux/compiler.h:353:2: note: in expansion of macro 'compiletime_assert' 353 | compiletime_assert(__native_word(t), | ^~~~~~~~~~~~~~~~~~ include/asm-generic/barrier.h:187:2: note: in expansion of macro 'compiletime_assert_atomic_type' 187 | compiletime_assert_atomic_type(*p); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 354 | cons_pos = smp_load_acquire(&rb->consumer_pos) & rb->mask; | ^~~~~~~~~~~~~~~~ vim +/smp_load_acquire +354 kernel/bpf/ringbuf.c 332 333 static void bpf_ringbuf_commit(void *sample, bool discard) 334 { 335 unsigned long rec_pos, cons_pos; 336 u32 new_meta, old_meta; 337 void *meta_ptr; 338 struct bpf_ringbuf *rb; 339 340 meta_ptr = sample - RINGBUF_META_SZ; 341 rb = bpf_ringbuf_restore_from_rec(meta_ptr); 342 old_meta = *(u32 *)meta_ptr; 343 new_meta = old_meta ^ RINGBUF_BUSY_BIT; 344 if (discard) 345 new_meta |= RINGBUF_DISCARD_BIT; 346 347 /* update metadata header with correct final size prefix */ 348 xchg((u32 *)meta_ptr, new_meta); 349 350 /* if consumer caught up and is waiting for our record, notify about 351 * new data availability 352 */ 353 rec_pos = (void *)meta_ptr - (void *)rb->data; 355 if (cons_pos == rec_pos) 356 wake_up_all(&rb->waitq); 357 } 358 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org