bpf: Allow attach TRACING programs through LINK_CREATE command
Allow attaching BTF-aware TRACING programs, previously attachable only through BPF_RAW_TRACEPOINT_OPEN command, through LINK_CREATE command: - BTF-aware raw tracepoints (tp_btf in libbpf lingo); - fentry/fexit/fmod_ret programs; - BPF LSM programs. This change converges all bpf_link-based attachments under LINK_CREATE command allowing to further extend the API with features like BPF cookie under "multiplexed" link_create section of bpf_attr. Non-BTF-aware raw tracepoints are left under BPF_RAW_TRACEPOINT_OPEN, but there is nothing preventing opening them up to LINK_CREATE as well. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Kuifeng Lee <kuifeng@fb.com> Link: https://lore.kernel.org/bpf/20220421033945.3602803-2-andrii@kernel.org
This commit is contained in:
Andrii Nakryiko
Daniel Borkmann
parent
e8c5e1a0f7
commit
df86ca0d2f
@ -3030,66 +3030,45 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
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}
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#endif /* CONFIG_PERF_EVENTS */
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#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
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static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
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static int bpf_raw_tp_link_attach(struct bpf_prog *prog,
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const char __user *user_tp_name)
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{
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struct bpf_link_primer link_primer;
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struct bpf_raw_tp_link *link;
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struct bpf_raw_event_map *btp;
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struct bpf_prog *prog;
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const char *tp_name;
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char buf[128];
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int err;
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if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
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return -EINVAL;
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prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
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if (IS_ERR(prog))
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return PTR_ERR(prog);
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switch (prog->type) {
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case BPF_PROG_TYPE_TRACING:
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case BPF_PROG_TYPE_EXT:
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case BPF_PROG_TYPE_LSM:
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if (attr->raw_tracepoint.name) {
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if (user_tp_name)
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/* The attach point for this category of programs
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* should be specified via btf_id during program load.
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*/
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err = -EINVAL;
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goto out_put_prog;
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}
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return -EINVAL;
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if (prog->type == BPF_PROG_TYPE_TRACING &&
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prog->expected_attach_type == BPF_TRACE_RAW_TP) {
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tp_name = prog->aux->attach_func_name;
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break;
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}
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err = bpf_tracing_prog_attach(prog, 0, 0);
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if (err >= 0)
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return err;
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goto out_put_prog;
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return bpf_tracing_prog_attach(prog, 0, 0);
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case BPF_PROG_TYPE_RAW_TRACEPOINT:
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case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
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if (strncpy_from_user(buf,
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u64_to_user_ptr(attr->raw_tracepoint.name),
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sizeof(buf) - 1) < 0) {
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err = -EFAULT;
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goto out_put_prog;
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}
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if (strncpy_from_user(buf, user_tp_name, sizeof(buf) - 1) < 0)
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return -EFAULT;
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buf[sizeof(buf) - 1] = 0;
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tp_name = buf;
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break;
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default:
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err = -EINVAL;
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goto out_put_prog;
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return -EINVAL;
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}
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btp = bpf_get_raw_tracepoint(tp_name);
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if (!btp) {
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err = -ENOENT;
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goto out_put_prog;
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}
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if (!btp)
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return -ENOENT;
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link = kzalloc(sizeof(*link), GFP_USER);
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if (!link) {
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@ -3116,11 +3095,29 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
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out_put_btp:
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bpf_put_raw_tracepoint(btp);
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out_put_prog:
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bpf_prog_put(prog);
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return err;
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}
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#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
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static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
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{
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struct bpf_prog *prog;
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int fd;
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if (CHECK_ATTR(BPF_RAW_TRACEPOINT_OPEN))
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return -EINVAL;
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prog = bpf_prog_get(attr->raw_tracepoint.prog_fd);
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if (IS_ERR(prog))
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return PTR_ERR(prog);
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fd = bpf_raw_tp_link_attach(prog, u64_to_user_ptr(attr->raw_tracepoint.name));
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if (fd < 0)
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bpf_prog_put(prog);
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return fd;
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}
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static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
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enum bpf_attach_type attach_type)
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{
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@ -3189,7 +3186,13 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
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case BPF_CGROUP_SETSOCKOPT:
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return BPF_PROG_TYPE_CGROUP_SOCKOPT;
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case BPF_TRACE_ITER:
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case BPF_TRACE_RAW_TP:
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case BPF_TRACE_FENTRY:
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case BPF_TRACE_FEXIT:
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case BPF_MODIFY_RETURN:
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return BPF_PROG_TYPE_TRACING;
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case BPF_LSM_MAC:
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return BPF_PROG_TYPE_LSM;
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case BPF_SK_LOOKUP:
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return BPF_PROG_TYPE_SK_LOOKUP;
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case BPF_XDP:
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@ -4246,21 +4249,6 @@ err_put:
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return err;
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}
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static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
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struct bpf_prog *prog)
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{
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if (attr->link_create.attach_type != prog->expected_attach_type)
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return -EINVAL;
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if (prog->expected_attach_type == BPF_TRACE_ITER)
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return bpf_iter_link_attach(attr, uattr, prog);
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else if (prog->type == BPF_PROG_TYPE_EXT)
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return bpf_tracing_prog_attach(prog,
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attr->link_create.target_fd,
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attr->link_create.target_btf_id);
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return -EINVAL;
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}
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#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies
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static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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{
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@ -4282,15 +4270,13 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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switch (prog->type) {
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case BPF_PROG_TYPE_EXT:
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ret = tracing_bpf_link_attach(attr, uattr, prog);
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goto out;
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break;
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case BPF_PROG_TYPE_PERF_EVENT:
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case BPF_PROG_TYPE_TRACEPOINT:
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if (attr->link_create.attach_type != BPF_PERF_EVENT) {
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ret = -EINVAL;
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goto out;
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}
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ptype = prog->type;
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break;
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case BPF_PROG_TYPE_KPROBE:
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if (attr->link_create.attach_type != BPF_PERF_EVENT &&
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@ -4298,7 +4284,6 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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ret = -EINVAL;
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goto out;
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}
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ptype = prog->type;
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break;
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default:
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ptype = attach_type_to_prog_type(attr->link_create.attach_type);
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@ -4309,7 +4294,7 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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break;
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}
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switch (ptype) {
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switch (prog->type) {
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case BPF_PROG_TYPE_CGROUP_SKB:
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case BPF_PROG_TYPE_CGROUP_SOCK:
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case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
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@ -4319,8 +4304,25 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
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case BPF_PROG_TYPE_CGROUP_SOCKOPT:
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ret = cgroup_bpf_link_attach(attr, prog);
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break;
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case BPF_PROG_TYPE_EXT:
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ret = bpf_tracing_prog_attach(prog,
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attr->link_create.target_fd,
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attr->link_create.target_btf_id);
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break;
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case BPF_PROG_TYPE_LSM:
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case BPF_PROG_TYPE_TRACING:
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ret = tracing_bpf_link_attach(attr, uattr, prog);
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if (attr->link_create.attach_type != prog->expected_attach_type) {
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ret = -EINVAL;
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goto out;
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}
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if (prog->expected_attach_type == BPF_TRACE_RAW_TP)
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ret = bpf_raw_tp_link_attach(prog, NULL);
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else if (prog->expected_attach_type == BPF_TRACE_ITER)
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ret = bpf_iter_link_attach(attr, uattr, prog);
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else
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ret = bpf_tracing_prog_attach(prog,
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attr->link_create.target_fd,
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attr->link_create.target_btf_id);
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break;
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case BPF_PROG_TYPE_FLOW_DISSECTOR:
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case BPF_PROG_TYPE_SK_LOOKUP:
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