CVE-2023-52992 bpf: Skip task with pid=1 in send_signal_common()

In the Linux kernel, the following vulnerability has been resolved: bpf: Skip task with pid=1 in sendsignalcommon The following kernel panic can be triggered when a task with pid=1 attaches a prog that attempts to send killing signal to itself, also see 1 for more details: Kernel panic - not...