Re: [PATCH v2 bpf-next 1/2] bpf: separate bpf_get_[stack|stackid] for perf events BPF

[kernel test robot]

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-perf_events-with-PEBS/20200715-133118
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@xxxxxxxxx>

All errors (new ones prefixed by >>):

>> kernel/bpf/stackmap.c:698:26: 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]
                   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))
 > 698			return __bpf_get_stack(ctx->regs, NULL, NULL, buf, size, flags);
   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@xxxxxxxxxxxx

Attachment: .config.gz
Description: application/gzip