bpf: remove tracepoints from bpf core

tracepoints to bpf core were added as a way to provide introspection
to bpf programs and maps, but after some time it became clear that
this approach is inadequate, so prog_id, map_id and corresponding
get_next_id, get_fd_by_id, get_info_by_fd, prog_query APIs were
introduced and fully adopted by bpftool and other applications.
The tracepoints in bpf core started to rot and causing syzbot warnings:
WARNING: CPU: 0 PID: 3008 at kernel/trace/trace_event_perf.c:274
Kernel panic - not syncing: panic_on_warn set ...
perf_trace_bpf_map_keyval+0x260/0xbd0 include/trace/events/bpf.h:228
trace_bpf_map_update_elem include/trace/events/bpf.h:274 [inline]
map_update_elem kernel/bpf/syscall.c:597 [inline]
SYSC_bpf kernel/bpf/syscall.c:1478 [inline]
Hence this patch deletes tracepoints in bpf core.

Reported-by: Eric Biggers <[email protected]>
Reported-by: syzbot <bot+a9dbb3c3e64b62536a4bc5ee7bbd4ca627566188@syzkaller.appspotmail.com>
Signed-off-by: Alexei Starovoitov <[email protected]>
Acked-by: David S. Miller <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>

Author: Alexei Starovoitov

MAINTAINERS

@@ -2727,7 +2727,6 @@ F:	Documentation/networking/filter.txt
 F:	Documentation/bpf/
 F:	include/linux/bpf*
 F:	include/linux/filter.h
-F:	include/trace/events/bpf.h
 F:	include/trace/events/xdp.h
 F:	include/uapi/linux/bpf*
 F:	include/uapi/linux/filter.h

include/linux/bpf_trace.h

@@ -2,7 +2,6 @@
 #ifndef __LINUX_BPF_TRACE_H__
 #define __LINUX_BPF_TRACE_H__
 
-#include <trace/events/bpf.h>
 #include <trace/events/xdp.h>
 
 #endif /* __LINUX_BPF_TRACE_H__ */

include/trace/events/bpf.h

@@ -1845,9 +1845,3 @@ int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
 #include <linux/bpf_trace.h>
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
-
-/* These are only used within the BPF_SYSCALL code */
-#ifdef CONFIG_BPF_SYSCALL
-EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
-EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);
-#endif