bpf: disable and restore preemption in __BPF_PROG_RUN_ARRAY

bpf: disable and restore preemption in __BPF_PROG_RUN_ARRAY

Running bpf programs requires disabled preemption,
however at least some* of the BPF_PROG_RUN_ARRAY users
do not follow this rule.

To fix this bug, and also to make it not happen in the future,
let's add explicit preemption disabling/re-enabling
to the __BPF_PROG_RUN_ARRAY code.

* for example:
 [   17.624472] RIP: 0010:__cgroup_bpf_run_filter_sk+0x1c4/0x1d0
 ...
 [   17.640890]  inet6_create+0x3eb/0x520
 [   17.641405]  __sock_create+0x242/0x340
 [   17.641939]  __sys_socket+0x57/0xe0
 [   17.642370]  ? trace_hardirqs_off_thunk+0x1a/0x1c
 [   17.642944]  SyS_socket+0xa/0x10
 [   17.643357]  do_syscall_64+0x79/0x220
 [   17.643879]  entry_SYSCALL_64_after_hwframe+0x42/0xb7

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>