Failed to load BPF program trace_connect_v4_return: Permission denied

I'm trying to trace tcp connection using `tools/tcptracer.py`. But following error messages appears. I found some similar problem, #382 #1007 #829 ..., but I don't know how to fix it.

`uname -r` : `4.4.0-75-generic`

root@iovisor-node:~/bcc/tools# ./tcptracer.py
bpf: Permission denied
0: (79) r7 = *(u64 *)(r1 +80)
1: (85) call 14
2: (7b) *(u64 *)(r10 -24) = r0
3: (18) r1 = 0x7a61e780
5: (bf) r2 = r10
6: (07) r2 += -24
7: (85) call 1
8: (bf) r6 = r0
9: (15) if r6 == 0x0 goto pc+88
R0=map_value_or_null(ks=8,vs=8) R6=map_value(ks=8,vs=8) R7=inv R10=fp
10: (18) r1 = 0x7a61e780
12: (bf) r2 = r10
13: (07) r2 += -24
14: (85) call 3
15: (67) r7 <<= 32
16: (77) r7 >>= 32
17: (55) if r7 != 0x0 goto pc+80
R0=inv R6=map_value(ks=8,vs=8) R7=imm0 R10=fp
18: (79) r6 = *(u64 *)(r6 +0)
19: (b7) r1 = 0
20: (63) *(u32 *)(r10 -32) = r1
21: (7b) *(u64 *)(r10 -40) = r1
22: (63) *(u32 *)(r10 -4) = r1
23: (63) *(u32 *)(r10 -8) = r1
24: (63) *(u32 *)(r10 -12) = r1
25: (6b) *(u16 *)(r10 -14) = r1
26: (6b) *(u16 *)(r10 -16) = r1
27: (bf) r3 = r6
28: (07) r3 += 4
29: (bf) r1 = r10
30: (07) r1 += -4
31: (b7) r2 = 4
32: (85) call 4
33: (bf) r1 = r10
34: (07) r1 += -8
35: (b7) r2 = 4
36: (bf) r3 = r6
37: (85) call 4
38: (bf) r3 = r6
39: (07) r3 += 720
40: (bf) r1 = r10
41: (07) r1 += -14
42: (b7) r2 = 2
43: (85) call 4
44: (bf) r3 = r6
45: (07) r3 += 12
46: (bf) r1 = r10
47: (07) r1 += -16
48: (b7) r2 = 2
49: (85) call 4
50: (07) r6 += 48
51: (bf) r1 = r10
52: (07) r1 += -64
53: (b7) r2 = 8
54: (bf) r3 = r6
55: (85) call 4
invalid indirect read from stack off -64+0 size 8

Traceback (most recent call last):
File "./tcptracer.py", line 530, in
b.attach_kretprobe(event="tcp_v4_connect", fn_name="trace_connect_v4_return")
File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 551, in attach_kretprobe
fn = self.load_func(fn_name, BPF.KPROBE)
File "/usr/lib/python2.7/dist-packages/bcc/__init__.py", line 345, in load_func
(func_name, errstr))
Exception: Failed to load BPF program trace_connect_v4_return: Permission denied

Start by reproducing the failure with tools/tcptracer.py on the reported 4.4.0-75-generic kernel, then inspect the attach_kretprobe call at line 530 and the verifier output. Compare the failing trace_connect_v4_return program with the related issues #382, #1007, and #829. Done means tcptracer.py loads the BPF program and traces TCP connections without the verifier error.

Written by the indexing model from the issue text.