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Merge branch 'bpf-cleanup-btf-raw-tp' 

Alexei Starovoitov says:

====================
v1->v2: addressed Andrii's feedback

When BTF-enabled raw_tp were introduced the plan was to follow up
with BTF-enabled kprobe and kretprobe reusing PROG_RAW_TRACEPOINT
and PROG_KPROBE types. But k[ret]probe expect pt_regs while
BTF-enabled program ctx will be the same as raw_tp.
kretprobe is indistinguishable from kprobe while BTF-enabled
kretprobe will have access to retval while kprobe will not.
Hence PROG_KPROBE type is not reusable and reusing
PROG_RAW_TRACEPOINT no longer fits well.
Hence introduce 'umbrella' prog type BPF_PROG_TYPE_TRACING
that will cover different BTF-enabled tracing attach points.
The changes make libbpf side cleaner as well.
check_attach_btf_id() is cleaner too.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Daniel Borkmann 2019-10-31 15:16:59 +01:00
parent af91acbc62 12a8654b2e
commit 0608711460
13 changed files with 142 additions and 49 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/bpf.h
View File

@ -373,6 +373,11 @@ enum bpf_cgroup_storage_type {
#define MAX_BPF_CGROUP_STORAGE_TYPE __BPF_CGROUP_STORAGE_MAX
/* The longest tracepoint has 12 args.
* See include/trace/bpf_probe.h
*/
#define MAX_BPF_FUNC_ARGS 12
struct bpf_prog_stats {
u64 cnt;
u64 nsecs;

1
include/linux/bpf_types.h
View File

@ -26,6 +26,7 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint)
BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event)
BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint)
BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, raw_tracepoint_writable)
BPF_PROG_TYPE(BPF_PROG_TYPE_TRACING, tracing)
#endif
#ifdef CONFIG_CGROUP_BPF
BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev)

2
include/uapi/linux/bpf.h
View File

@ -173,6 +173,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_PROG_TYPE_TRACING,
};
enum bpf_attach_type {
@ -199,6 +200,7 @@ enum bpf_attach_type {
BPF_CGROUP_UDP6_RECVMSG,
BPF_CGROUP_GETSOCKOPT,
BPF_CGROUP_SETSOCKOPT,
BPF_TRACE_RAW_TP,
__MAX_BPF_ATTACH_TYPE
};

6
kernel/bpf/syscall.c
View File

@ -1571,7 +1571,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
u32 btf_id)
{
switch (prog_type) {
case BPF_PROG_TYPE_RAW_TRACEPOINT:
case BPF_PROG_TYPE_TRACING:
if (btf_id > BTF_MAX_TYPE)
return -EINVAL;
break;
@ -1833,13 +1833,13 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
return PTR_ERR(prog);
if (prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT &&
prog->type != BPF_PROG_TYPE_TRACING &&
prog->type != BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE) {
err = -EINVAL;
goto out_put_prog;
}
if (prog->type == BPF_PROG_TYPE_RAW_TRACEPOINT &&
prog->aux->attach_btf_id) {
if (prog->type == BPF_PROG_TYPE_TRACING) {
if (attr->raw_tracepoint.name) {
/* raw_tp name should not be specified in raw_tp
* programs that were verified via in-kernel BTF info

34
kernel/bpf/verifier.c
View File

@ -9381,24 +9381,36 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
{
struct bpf_prog *prog = env->prog;
u32 btf_id = prog->aux->attach_btf_id;
const char prefix[] = "btf_trace_";
const struct btf_type *t;
const char *tname;
if (prog->type == BPF_PROG_TYPE_RAW_TRACEPOINT && btf_id) {
const char prefix[] = "btf_trace_";
if (prog->type != BPF_PROG_TYPE_TRACING)
return 0;
t = btf_type_by_id(btf_vmlinux, btf_id);
if (!t) {
verbose(env, "attach_btf_id %u is invalid\n", btf_id);
return -EINVAL;
}
if (!btf_id) {
verbose(env, "Tracing programs must provide btf_id\n");
return -EINVAL;
}
t = btf_type_by_id(btf_vmlinux, btf_id);
if (!t) {
verbose(env, "attach_btf_id %u is invalid\n", btf_id);
return -EINVAL;
}
tname = btf_name_by_offset(btf_vmlinux, t->name_off);
if (!tname) {
verbose(env, "attach_btf_id %u doesn't have a name\n", btf_id);
return -EINVAL;
}
switch (prog->expected_attach_type) {
case BPF_TRACE_RAW_TP:
if (!btf_type_is_typedef(t)) {
verbose(env, "attach_btf_id %u is not a typedef\n",
btf_id);
return -EINVAL;
}
tname = btf_name_by_offset(btf_vmlinux, t->name_off);
if (!tname || strncmp(prefix, tname, sizeof(prefix) - 1)) {
if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
verbose(env, "attach_btf_id %u points to wrong type name %s\n",
btf_id, tname);
return -EINVAL;
@ -9419,8 +9431,10 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
prog->aux->attach_func_name = tname;
prog->aux->attach_func_proto = t;
prog->aux->attach_btf_trace = true;
return 0;
default:
return -EINVAL;
}
return 0;
}
int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,

44
kernel/trace/bpf_trace.c
View File

@ -1055,10 +1055,6 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
switch (func_id) {
case BPF_FUNC_perf_event_output:
return &bpf_perf_event_output_proto_raw_tp;
#ifdef CONFIG_NET
case BPF_FUNC_skb_output:
return &bpf_skb_output_proto;
#endif
case BPF_FUNC_get_stackid:
return &bpf_get_stackid_proto_raw_tp;
case BPF_FUNC_get_stack:
@ -1068,20 +1064,44 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
}
}
static const struct bpf_func_proto *
tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
{
switch (func_id) {
#ifdef CONFIG_NET
case BPF_FUNC_skb_output:
return &bpf_skb_output_proto;
#endif
default:
return raw_tp_prog_func_proto(func_id, prog);
}
}
static bool raw_tp_prog_is_valid_access(int off, int size,
enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
{
/* largest tracepoint in the kernel has 12 args */
if (off < 0 || off >= sizeof(__u64) * 12)
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
return true;
}
static bool tracing_prog_is_valid_access(int off, int size,
enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
{
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
if (!prog->aux->attach_btf_id)
return true;
return btf_ctx_access(off, size, type, prog, info);
}
@ -1093,6 +1113,14 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = {
const struct bpf_prog_ops raw_tracepoint_prog_ops = {
};
const struct bpf_verifier_ops tracing_verifier_ops = {
.get_func_proto = tracing_prog_func_proto,
.is_valid_access = tracing_prog_is_valid_access,
};
const struct bpf_prog_ops tracing_prog_ops = {
};
static bool raw_tp_writable_prog_is_valid_access(int off, int size,
enum bpf_access_type type,
const struct bpf_prog *prog,

2
tools/include/uapi/linux/bpf.h
View File

@ -173,6 +173,7 @@ enum bpf_prog_type {
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_PROG_TYPE_TRACING,
};
enum bpf_attach_type {
@ -199,6 +200,7 @@ enum bpf_attach_type {
BPF_CGROUP_UDP6_RECVMSG,
BPF_CGROUP_GETSOCKOPT,
BPF_CGROUP_SETSOCKOPT,
BPF_TRACE_RAW_TP,
__MAX_BPF_ATTACH_TYPE
};

8
tools/lib/bpf/bpf.c
View File

@ -228,9 +228,10 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
memset(&attr, 0, sizeof(attr));
attr.prog_type = load_attr->prog_type;
attr.expected_attach_type = load_attr->expected_attach_type;
if (attr.prog_type == BPF_PROG_TYPE_RAW_TRACEPOINT)
/* expected_attach_type is ignored for tracing progs */
attr.attach_btf_id = attr.expected_attach_type;
if (attr.prog_type == BPF_PROG_TYPE_TRACING)
attr.attach_btf_id = load_attr->attach_btf_id;
else
attr.prog_ifindex = load_attr->prog_ifindex;
attr.insn_cnt = (__u32)load_attr->insns_cnt;
attr.insns = ptr_to_u64(load_attr->insns);
attr.license = ptr_to_u64(load_attr->license);
@ -245,7 +246,6 @@ int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
}
attr.kern_version = load_attr->kern_version;
attr.prog_ifindex = load_attr->prog_ifindex;
attr.prog_btf_fd = load_attr->prog_btf_fd;
attr.func_info_rec_size = load_attr->func_info_rec_size;
attr.func_info_cnt = load_attr->func_info_cnt;

5
tools/lib/bpf/bpf.h
View File

@ -78,7 +78,10 @@ struct bpf_load_program_attr {
size_t insns_cnt;
const char *license;
__u32 kern_version;
__u32 prog_ifindex;
union {
__u32 prog_ifindex;
__u32 attach_btf_id;
};
__u32 prog_btf_fd;
__u32 func_info_rec_size;
const void *func_info;

79
tools/lib/bpf/libbpf.c
View File

@ -188,6 +188,7 @@ struct bpf_program {
bpf_program_clear_priv_t clear_priv;
enum bpf_attach_type expected_attach_type;
__u32 attach_btf_id;
void *func_info;
__u32 func_info_rec_size;
__u32 func_info_cnt;
@ -3446,6 +3447,7 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
load_attr.line_info_cnt = prog->line_info_cnt;
load_attr.log_level = prog->log_level;
load_attr.prog_flags = prog->prog_flags;
load_attr.attach_btf_id = prog->attach_btf_id;
retry_load:
log_buf = malloc(log_buf_size);
@ -3607,6 +3609,8 @@ bpf_object__load_progs(struct bpf_object *obj, int log_level)
return 0;
}
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id);
static struct bpf_object *
__bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
struct bpf_object_open_opts *opts)
@ -3656,6 +3660,7 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_object__for_each_program(prog, obj) {
enum bpf_prog_type prog_type;
enum bpf_attach_type attach_type;
__u32 btf_id;
err = libbpf_prog_type_by_name(prog->section_name, &prog_type,
&attach_type);
@ -3667,6 +3672,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_program__set_type(prog, prog_type);
bpf_program__set_expected_attach_type(prog, attach_type);
if (prog_type == BPF_PROG_TYPE_TRACING) {
err = libbpf_attach_btf_id_by_name(prog->section_name, &btf_id);
if (err)
goto out;
prog->attach_btf_id = btf_id;
}
}
return obj;
@ -4518,6 +4529,7 @@ BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
BPF_PROG_TYPE_FNS(raw_tracepoint, BPF_PROG_TYPE_RAW_TRACEPOINT);
BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
BPF_PROG_TYPE_FNS(tracing, BPF_PROG_TYPE_TRACING);
enum bpf_attach_type
bpf_program__get_expected_attach_type(struct bpf_program *prog)
@ -4546,7 +4558,8 @@ void bpf_program__set_expected_attach_type(struct bpf_program *prog,
BPF_PROG_SEC_IMPL(string, ptype, eatype, 1, 0, eatype)
/* Programs that use BTF to identify attach point */
#define BPF_PROG_BTF(string, ptype) BPF_PROG_SEC_IMPL(string, ptype, 0, 0, 1, 0)
#define BPF_PROG_BTF(string, ptype, eatype) \
BPF_PROG_SEC_IMPL(string, ptype, eatype, 0, 1, 0)
/* Programs that can be attached but attach type can't be identified by section
* name. Kept for backward compatibility.
@ -4573,7 +4586,8 @@ static const struct {
BPF_PROG_SEC("tp/", BPF_PROG_TYPE_TRACEPOINT),
BPF_PROG_SEC("raw_tracepoint/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_SEC("raw_tp/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_RAW_TRACEPOINT),
BPF_PROG_BTF("tp_btf/", BPF_PROG_TYPE_TRACING,
BPF_TRACE_RAW_TP),
BPF_PROG_SEC("xdp", BPF_PROG_TYPE_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),
@ -4678,27 +4692,6 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
continue;
*prog_type = section_names[i].prog_type;
*expected_attach_type = section_names[i].expected_attach_type;
if (section_names[i].is_attach_btf) {
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf_name[128] = "btf_trace_";
char *dst = raw_tp_btf_name + sizeof("btf_trace_") - 1;
int ret;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
sizeof(raw_tp_btf_name) - sizeof("btf_trace_"));
ret = btf__find_by_name(btf, raw_tp_btf_name);
btf__free(btf);
if (ret <= 0) {
pr_warn("%s is not found in vmlinux BTF\n", dst);
return -EINVAL;
}
*expected_attach_type = ret;
}
return 0;
}
pr_warn("failed to guess program type based on ELF section name '%s'\n", name);
@ -4711,6 +4704,46 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
return -ESRCH;
}
#define BTF_PREFIX "btf_trace_"
static int libbpf_attach_btf_id_by_name(const char *name, __u32 *btf_id)
{
struct btf *btf = bpf_core_find_kernel_btf();
char raw_tp_btf_name[128] = BTF_PREFIX;
char *dst = raw_tp_btf_name + sizeof(BTF_PREFIX) - 1;
int ret, i, err = -EINVAL;
if (IS_ERR(btf)) {
pr_warn("vmlinux BTF is not found\n");
return -EINVAL;
}
if (!name)
goto out;
for (i = 0; i < ARRAY_SIZE(section_names); i++) {
if (!section_names[i].is_attach_btf)
continue;
if (strncmp(name, section_names[i].sec, section_names[i].len))
continue;
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
sizeof(raw_tp_btf_name) - sizeof(BTF_PREFIX));
ret = btf__find_by_name(btf, raw_tp_btf_name);
if (ret <= 0) {
pr_warn("%s is not found in vmlinux BTF\n", dst);
goto out;
}
*btf_id = ret;
err = 0;
goto out;
}
pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name);
err = -ESRCH;
out:
btf__free(btf);
return err;
}
int libbpf_attach_type_by_name(const char *name,
enum bpf_attach_type *attach_type)
{

2
tools/lib/bpf/libbpf.h
View File

@ -307,6 +307,7 @@ LIBBPF_API int bpf_program__set_sched_cls(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_sched_act(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_xdp(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_perf_event(struct bpf_program *prog);
LIBBPF_API int bpf_program__set_tracing(struct bpf_program *prog);
LIBBPF_API enum bpf_prog_type bpf_program__get_type(struct bpf_program *prog);
LIBBPF_API void bpf_program__set_type(struct bpf_program *prog,
@ -326,6 +327,7 @@ LIBBPF_API bool bpf_program__is_sched_cls(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_sched_act(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_xdp(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_perf_event(const struct bpf_program *prog);
LIBBPF_API bool bpf_program__is_tracing(const struct bpf_program *prog);
/*
* No need for __attribute__((packed)), all members of 'bpf_map_def'

2
tools/lib/bpf/libbpf.map
View File

@ -197,4 +197,6 @@ LIBBPF_0.0.6 {
bpf_object__open_mem;
bpf_program__get_expected_attach_type;
bpf_program__get_type;
bpf_program__is_tracing;
bpf_program__set_tracing;
} LIBBPF_0.0.5;

1
tools/lib/bpf/libbpf_probes.c
View File

@ -102,6 +102,7 @@ probe_load(enum bpf_prog_type prog_type, const struct bpf_insn *insns,
case BPF_PROG_TYPE_FLOW_DISSECTOR:
case BPF_PROG_TYPE_CGROUP_SYSCTL:
case BPF_PROG_TYPE_CGROUP_SOCKOPT:
case BPF_PROG_TYPE_TRACING:
default:
break;
}