[PATCH bpf 3/3] bpf: show main program address in bpf_prog_info->jited_ksyms

[Song Liu]

Currently, when there is not subprog (prog->aux->func_cnt == 0),
bpf_prog_info does not return any jited_ksyms. This patch adds
main program address (prog->bpf_func) to jited_ksyms.

Signed-off-by: Song Liu <songliubrav...@fb.com>
---
 kernel/bpf/syscall.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 34a9eef5992c..7293b17ca62a 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2158,7 +2158,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
        }
 
        ulen = info.nr_jited_ksyms;
-       info.nr_jited_ksyms = prog->aux->func_cnt;
+       info.nr_jited_ksyms = prog->aux->func_cnt ? : 1;
        if (info.nr_jited_ksyms && ulen) {
                if (bpf_dump_raw_ok()) {
                        u64 __user *user_ksyms;
@@ -2170,9 +2170,17 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog,
                         */
                        ulen = min_t(u32, info.nr_jited_ksyms, ulen);
                        user_ksyms = u64_to_user_ptr(info.jited_ksyms);
-                       for (i = 0; i < ulen; i++) {
-                               ksym_addr = (ulong) 
prog->aux->func[i]->bpf_func;
-                               if (put_user((u64) ksym_addr, &user_ksyms[i]))
+                       if (prog->aux->func_cnt) {
+                               for (i = 0; i < ulen; i++) {
+                                       ksym_addr = (ulong)
+                                               prog->aux->func[i]->bpf_func;
+                                       if (put_user((u64) ksym_addr,
+                                                    &user_ksyms[i]))
+                                               return -EFAULT;
+                               }
+                       } else {
+                               ksym_addr = (ulong) prog->bpf_func;
+                               if (put_user((u64) ksym_addr, &user_ksyms[0]))
                                        return -EFAULT;
                        }
                } else {
-- 
2.17.1