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bpf: remove tracepoints from bpf core

PATCH In review Alexei Starovoitov 3 participants 3 messages Apr 29, 2018 – Apr 30, 2018

Subsystems (5)
Networking Network drivers BPF Tracing +1 more subsystems
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Alexei Starovoitov

author maintainer
#0 lore raw

PATCH 1/1 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]>
---
 MAINTAINERS                |   1 -
 include/linux/bpf_trace.h  |   1 -
 include/trace/events/bpf.h | 355 ---------------------------------------------
 kernel/bpf/core.c          |   6 -
 kernel/bpf/inode.c         |  16 +-
 kernel/bpf/syscall.c       |  11 --
 6 files changed, 1 insertion(+), 389 deletions(-)
 delete mode 100644 include/trace/events/bpf.h
MAINTAINERS +0 -1
index a52800867850..537fd17a211b 100644
@@ -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 +0 -1
index e6fe98ae3794..ddf896abcfb6 100644
@@ -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 deleted +0 -355

355 lines not on this page · raw message

kernel/bpf/core.c +0 -6
index ba03ec39efb3..133bff8adda3 100644
@@ -1840,9 +1840,3 @@ 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
kernel/bpf/inode.c +1 -15
index a41343009ccc..ed13645bd80c 100644
@@ -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;
kernel/bpf/syscall.c +0 -11
index 0bd2944eafb9..4388fac70685 100644
@@ -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 @@ static int map_get_next_key(union bpf_attr *attr)
 	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);
 

@@ -1196,8 +1188,6 @@ struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
 {
 	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, attach_drv);
 
-	if (!IS_ERR(prog))
-		trace_bpf_prog_get_type(prog);
 	return prog;
 }
 EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);

@@ -1373,7 +1363,6 @@ 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:
Signature · 1 line
2.9.5
maintainer Acked-by on v1 1/1
#1 lore raw

From: Alexei Starovoitov <[email protected]>
Date: Sat, 28 Apr 2018 19:56:37 -0700

Quoted 12 lines

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]
Quoted 5 lines

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]>
maintainer
#2 lore raw
Quoted 17 lines · David Miller

From: Alexei Starovoitov <[email protected]>
Date: Sat, 28 Apr 2018 19:56:37 -0700

Quoted 14 lines

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.

Quoted 5 lines
Quoted 3 lines
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]>

Fully agree, applied to bpf-next, thanks!