bpf: Guard against accessing NULL ptregs in bpfgettaskstack()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.16.5 by commit b82ef4985a6d05e80f604624332430351df7b79a, it was introduced in version v5.9 by commit fa28dcb82a38f8e3993b0fae9106b1a80b59e4f0. For more details please see the references link.