Hi Song, I love your patch! Yet something to improve: [auto build test ERROR on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Song-Liu/bpf-fix-stackmap-on-per... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master config: arm64-randconfig-r004-20200716 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project ed6b578040a85977026c93bf4188f996148f3218) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): return __bpf_get_stack(ctx->regs, NULL, NULL, buf, size, flags); ^~~~~~~~~ kernel/bpf/stackmap.c:581:45: note: passing argument to parameter 'regs' here static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, ^ kernel/bpf/stackmap.c:726:26: error: incompatible pointer types passing 'bpf_user_pt_regs_t *' (aka 'struct user_pt_regs *') to parameter of type 'struct pt_regs *' [-Werror,-Wincompatible-pointer-types] ret = __bpf_get_stack(ctx->regs, NULL, trace, buf, ^~~~~~~~~ kernel/bpf/stackmap.c:581:45: note: passing argument to parameter 'regs' here static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, ^ kernel/bpf/stackmap.c:740:26: error: incompatible pointer types passing 'bpf_user_pt_regs_t *' (aka 'struct user_pt_regs *') to parameter of type 'struct pt_regs *' [-Werror,-Wincompatible-pointer-types] ret = __bpf_get_stack(ctx->regs, NULL, trace, buf, ^~~~~~~~~ kernel/bpf/stackmap.c:581:45: note: passing argument to parameter 'regs' here static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, ^ kernel/bpf/stackmap.c:745:25: error: incompatible pointer types passing 'bpf_user_pt_regs_t *' (aka 'struct user_pt_regs *') to parameter of type 'struct pt_regs *' [-Werror,-Wincompatible-pointer-types] return __bpf_get_stack(ctx->regs, NULL, trace, buf, size, flags); ^~~~~~~~~ kernel/bpf/stackmap.c:581:45: note: passing argument to parameter 'regs' here static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, ^ 4 errors generated. vim +698 kernel/bpf/stackmap.c 687 688 BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 689 void *, buf, u32, size, u64, flags) 690 { 691 struct perf_event *event = ctx->event; 692 struct perf_callchain_entry *trace; 693 bool has_kernel, has_user; 694 bool kernel, user; 695 int err = -EINVAL; 696 697 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 699 700 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 701 BPF_F_USER_BUILD_ID))) 702 goto clear; 703 704 user = flags & BPF_F_USER_STACK; 705 kernel = !user; 706 707 has_kernel = !event->attr.exclude_callchain_kernel; 708 has_user = !event->attr.exclude_callchain_user; 709 710 if ((kernel && !has_kernel) || (user && !has_user)) 711 goto clear; 712 713 err = -EFAULT; 714 trace = ctx->data->callchain; 715 if (!trace || (!has_kernel && !has_user)) 716 goto clear; 717 718 if (has_kernel && has_user) { 719 __u64 nr_kernel = count_kernel_ip(trace); 720 int ret; 721 722 if (kernel) { 723 __u64 nr = trace->nr; 724 725 trace->nr = nr_kernel; 726 ret = __bpf_get_stack(ctx->regs, NULL, trace, buf, 727 size, flags); 728 729 /* restore nr */ 730 trace->nr = nr; 731 } else { /* user */ 732 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 733 734 skip += nr_kernel; 735 if (skip > ~BPF_F_SKIP_FIELD_MASK) 736 goto clear; 737 738 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | 739 (skip & BPF_F_SKIP_FIELD_MASK); 740 ret = __bpf_get_stack(ctx->regs, NULL, trace, buf, 741 size, flags); 742 } 743 return ret; 744 } 745 return __bpf_get_stack(ctx->regs, NULL, trace, buf, size, flags); 746 clear: 747 memset(buf, 0, size); 748 return err; 749 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org