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 <ebiggers3@gmail.com>
Reported-by: syzbot <bot+a9dbb3c3e64b62536a4bc5ee7bbd4ca627566188@syzkaller.appspotmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

3 files changed, 2 insertions, 35 deletions

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 9349a5db3cf2..90feeba3a1a1 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -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
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index a41343009ccc..ed13645bd80c 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -429,13 +429,6 @@ int bpf_obj_pin_user(u32 ufd, const char __user *pathname)
 	ret = bpf_obj_do_pin(pname, raw, type);
 	if (ret != 0)
 		bpf_any_put(raw, type);
-	if ((trace_bpf_obj_pin_prog_enabled() ||
-	     trace_bpf_obj_pin_map_enabled()) && !ret) {
-		if (type == BPF_TYPE_PROG)
-			trace_bpf_obj_pin_prog(raw, ufd, pname);
-		if (type == BPF_TYPE_MAP)
-			trace_bpf_obj_pin_map(raw, ufd, pname);
-	}
 out:
 	putname(pname);
 	return ret;
@@ -502,15 +495,8 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
 	else
 		goto out;
 
-	if (ret < 0) {
+	if (ret < 0)
 		bpf_any_put(raw, type);
-	} else if (trace_bpf_obj_get_prog_enabled() ||
-		   trace_bpf_obj_get_map_enabled()) {
-		if (type == BPF_TYPE_PROG)
-			trace_bpf_obj_get_prog(raw, ret, pname);
-		if (type == BPF_TYPE_MAP)
-			trace_bpf_obj_get_map(raw, ret, pname);
-	}
 out:
 	putname(pname);
 	return ret;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0bd2944eafb9..263e13ede029 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -503,7 +503,6 @@ static int map_create(union bpf_attr *attr)
 		return err;
 	}
 
-	trace_bpf_map_create(map, err);
 	return err;
 
 free_map:
@@ -663,7 +662,6 @@ static int map_lookup_elem(union bpf_attr *attr)
 	if (copy_to_user(uvalue, value, value_size) != 0)
 		goto free_value;
 
-	trace_bpf_map_lookup_elem(map, ufd, key, value);
 	err = 0;
 
 free_value:
@@ -760,8 +758,6 @@ static int map_update_elem(union bpf_attr *attr)
 	__this_cpu_dec(bpf_prog_active);
 	preempt_enable();
 out:
-	if (!err)
-		trace_bpf_map_update_elem(map, ufd, key, value);
 free_value:
 	kfree(value);
 free_key:
@@ -814,8 +810,6 @@ static int map_delete_elem(union bpf_attr *attr)
 	__this_cpu_dec(bpf_prog_active);
 	preempt_enable();
 out:
-	if (!err)
-		trace_bpf_map_delete_elem(map, ufd, key);
 	kfree(key);
 err_put:
 	fdput(f);
@@ -879,7 +873,6 @@ out:
 	if (copy_to_user(unext_key, next_key, map->key_size) != 0)
 		goto free_next_key;
 
-	trace_bpf_map_next_key(map, ufd, key, next_key);
 	err = 0;
 
 free_next_key:
@@ -1027,7 +1020,6 @@ static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
 	if (atomic_dec_and_test(&prog->aux->refcnt)) {
 		int i;
 
-		trace_bpf_prog_put_rcu(prog);
 		/* bpf_prog_free_id() must be called first */
 		bpf_prog_free_id(prog, do_idr_lock);
 
@@ -1194,11 +1186,7 @@ struct bpf_prog *bpf_prog_get(u32 ufd)
 struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
 				       bool attach_drv)
 {
-	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, attach_drv);
-
-	if (!IS_ERR(prog))
-		trace_bpf_prog_get_type(prog);
-	return prog;
+	return __bpf_prog_get(ufd, &type, attach_drv);
 }
 EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);
 
@@ -1373,7 +1361,6 @@ static int bpf_prog_load(union bpf_attr *attr)
 	}
 
 	bpf_prog_kallsyms_add(prog);
-	trace_bpf_prog_load(prog, err);
 	return err;
 
 free_used_maps: