wrong bpf call offset when dumping xlated instructions

[xixiliguo]

Describe the bug

If prog was jited after loading, PC offset of bpf pseudo call was stored at field off, not imm.
please see below code for details
https://github.com/torvalds/linux/blob/87a132e73910e8689902aed7f2fc229d6908383b/kernel/bpf/verifier.c#L20783-L20795

currenct logic does not distinguish whether instructions was jited or not, just use imm as call offset .

How to reproduce

For xlated dump of same bpf c code , epbf-go show pc+1, but bpftool show pc+2

#include "bpf_endian.h"
#include "common.h"

char __license[] SEC("license") = "Dual MIT/GPL";


static __noinline int test(int i) {
	return i + 1;
}

int g = 1;

SEC("kprobe/hello")
int hello(struct pt_regs *ctx) {
	int m = test(g);
	return m + g;
}

func main() {
	objs := bpfObjects{}
	loadBpfObjects(&objs, nil)
	defer objs.Close()
	info, _ := objs.Hello.Info()
	ins, _ := info.Instructions()
	fmt.Printf("%+v\n", ins)
}

The output is as follows:

hello:
          ; int m = test(g);
         0: LoadMapValue dst: r1, fd: 274 off: 0
          ; int m = test(g);
         2: LdXMemW dst: r6 src: r1 off: 0 imm: 0
         3: MovReg dst: r1 src: r6
         4: Call 1                                                          // it's worng compared with bpftool 
          ; return m + g;
         5: AddReg dst: r0 src: r6
          ; return m + g;
         6: Exit
          ; static __noinline int test(int i) {
         7: MovReg dst: r0 src: r1
          ; return i + 1;
         8: AddImm dst: r0 imm: 1
          ; return i + 1;
         9: Exi

# bpftool prog load bpf_bpfel.o /sys/fs/bpf/test && bpftool prog dump xlated name hello opcodes
int hello(struct pt_regs * ctx):
; int m = test(g);
   0: (18) r1 = map[id:283][0]+0
       18 21 00 00 1b 01 00 00 00 00 00 00 00 00 00 00
; int m = test(g);
   2: (61) r6 = *(u32 *)(r1 +0)
       61 16 00 00 00 00 00 00
   3: (bf) r1 = r6
       bf 61 00 00 00 00 00 00
   4: (85) call pc+2#0xffffffffc01992d4                       // correct offset is extracted from field 'off', not imm
       85 10 02 00 01 00 00 00
; return m + g;
   5: (0f) r0 += r6
       0f 60 00 00 00 00 00 00
; return m + g;
   6: (95) exit
       95 00 00 00 00 00 00 00
int test(int i):
; static __noinline int test(int i) {
   7: (bf) r0 = r1
       bf 10 00 00 00 00 00 00
; return i + 1;
   8: (07) r0 += 1
       07 00 00 00 01 00 00 00
; return i + 1;
   9: (95) exit
       95 00 00 00 00 00 00 00

Version information

github.com/cilium/ebpf v0.17.3