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bpf: remove tracepoints from bpf core

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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>
This commit is contained in:
Alexei Starovoitov
2018-04-28 19:56:37 -07:00
committed by Daniel Borkmann
parent 34745aed51
commit 4d220ed0f8
6 changed files with 2 additions and 392 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
kernel/bpf/core.c
View File

@@ -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

16
kernel/bpf/inode.c
View File

@@ -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;

15
kernel/bpf/syscall.c
View File

@@ -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: