DNS Kretprobe May Not Function as Expected When Driver Version < 1.9.0.19

[Percivalll]

Describe the bug
DNS Kretprobe May Not Function as Expected When Driver Version < 1.9.0.19

To Reproduce
Manually simulated excessive DNS requests to observe whether the kretprobe had been unregistered. After waiting for a period, it was found that the kretprobe was reattached but remained in a disabled state.

Expected behavior
Re-enable kretprobe successfully.

OS information (please complete the following information):

• Distribution: CentOS
• Version 7.8
• Kernel info 3.10.0-1062.9.1.el7.x86_64

Additional context
I suspect that this issue was caused by not resetting kp->flags during dynamic reloading of Kretprobe. This problem no longer exists in the current version. This is just a reminder for others who might encounter similar issues.