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-rw-r--r--tools/lib/bpf/libbpf.c129
1 files changed, 106 insertions, 23 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 97eb6e5dd7c8..5401f2df463d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -132,6 +132,7 @@ static const char * const attach_type_name[] = {
[BPF_TRACE_UPROBE_MULTI] = "trace_uprobe_multi",
[BPF_NETKIT_PRIMARY] = "netkit_primary",
[BPF_NETKIT_PEER] = "netkit_peer",
+ [BPF_TRACE_KPROBE_SESSION] = "trace_kprobe_session",
};
static const char * const link_type_name[] = {
@@ -1127,6 +1128,7 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
const struct btf_type *mtype, *kern_mtype;
__u32 mtype_id, kern_mtype_id;
void *mdata, *kern_mdata;
+ struct bpf_program *prog;
__s64 msize, kern_msize;
__u32 moff, kern_moff;
__u32 kern_member_idx;
@@ -1144,18 +1146,28 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
kern_member = find_member_by_name(kern_btf, kern_type, mname);
if (!kern_member) {
- /* Skip all zeros or null fields if they are not
- * presented in the kernel BTF.
- */
- if (libbpf_is_mem_zeroed(mdata, msize)) {
- pr_info("struct_ops %s: member %s not found in kernel, skipping it as it's set to zero\n",
+ if (!libbpf_is_mem_zeroed(mdata, msize)) {
+ pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
map->name, mname);
- continue;
+ return -ENOTSUP;
}
- pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
+ if (st_ops->progs[i]) {
+ /* If we had declaratively set struct_ops callback, we need to
+ * force its autoload to false, because it doesn't have
+ * a chance of succeeding from POV of the current struct_ops map.
+ * If this program is still referenced somewhere else, though,
+ * then bpf_object_adjust_struct_ops_autoload() will update its
+ * autoload accordingly.
+ */
+ st_ops->progs[i]->autoload = false;
+ st_ops->progs[i] = NULL;
+ }
+
+ /* Skip all-zero/NULL fields if they are not present in the kernel BTF */
+ pr_info("struct_ops %s: member %s not found in kernel, skipping it as it's set to zero\n",
map->name, mname);
- return -ENOTSUP;
+ continue;
}
kern_member_idx = kern_member - btf_members(kern_type);
@@ -1181,13 +1193,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
}
if (btf_is_ptr(mtype)) {
- struct bpf_program *prog;
+ prog = *(void **)mdata;
+ /* just like for !kern_member case above, reset declaratively
+ * set (at compile time) program's autload to false,
+ * if user replaced it with another program or NULL
+ */
+ if (st_ops->progs[i] && st_ops->progs[i] != prog)
+ st_ops->progs[i]->autoload = false;
/* Update the value from the shadow type */
- prog = *(void **)mdata;
st_ops->progs[i] = prog;
if (!prog)
continue;
+
if (!is_valid_st_ops_program(obj, prog)) {
pr_warn("struct_ops init_kern %s: member %s is not a struct_ops program\n",
map->name, mname);
@@ -7354,7 +7372,11 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
__u32 log_level = prog->log_level;
int ret, err;
- if (prog->type == BPF_PROG_TYPE_UNSPEC) {
+ /* Be more helpful by rejecting programs that can't be validated early
+ * with more meaningful and actionable error message.
+ */
+ switch (prog->type) {
+ case BPF_PROG_TYPE_UNSPEC:
/*
* The program type must be set. Most likely we couldn't find a proper
* section definition at load time, and thus we didn't infer the type.
@@ -7362,6 +7384,15 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog
pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",
prog->name, prog->sec_name);
return -EINVAL;
+ case BPF_PROG_TYPE_STRUCT_OPS:
+ if (prog->attach_btf_id == 0) {
+ pr_warn("prog '%s': SEC(\"struct_ops\") program isn't referenced anywhere, did you forget to use it?\n",
+ prog->name);
+ return -EINVAL;
+ }
+ break;
+ default:
+ break;
}
if (!insns || !insns_cnt)
@@ -9272,6 +9303,7 @@ static int attach_tp(const struct bpf_program *prog, long cookie, struct bpf_lin
static int attach_raw_tp(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_trace(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_link **link);
static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_link **link);
@@ -9288,6 +9320,7 @@ static const struct bpf_sec_def section_defs[] = {
SEC_DEF("uretprobe.s+", KPROBE, 0, SEC_SLEEPABLE, attach_uprobe),
SEC_DEF("kprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
SEC_DEF("kretprobe.multi+", KPROBE, BPF_TRACE_KPROBE_MULTI, SEC_NONE, attach_kprobe_multi),
+ SEC_DEF("kprobe.session+", KPROBE, BPF_TRACE_KPROBE_SESSION, SEC_NONE, attach_kprobe_session),
SEC_DEF("uprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
SEC_DEF("uretprobe.multi+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_NONE, attach_uprobe_multi),
SEC_DEF("uprobe.multi.s+", KPROBE, BPF_TRACE_UPROBE_MULTI, SEC_SLEEPABLE, attach_uprobe_multi),
@@ -9858,16 +9891,28 @@ static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
enum bpf_attach_type attach_type,
int *btf_obj_fd, int *btf_type_id)
{
- int ret, i;
+ int ret, i, mod_len;
+ const char *fn_name, *mod_name = NULL;
- ret = find_attach_btf_id(obj->btf_vmlinux, attach_name, attach_type);
- if (ret > 0) {
- *btf_obj_fd = 0; /* vmlinux BTF */
- *btf_type_id = ret;
- return 0;
+ fn_name = strchr(attach_name, ':');
+ if (fn_name) {
+ mod_name = attach_name;
+ mod_len = fn_name - mod_name;
+ fn_name++;
+ }
+
+ if (!mod_name || strncmp(mod_name, "vmlinux", mod_len) == 0) {
+ ret = find_attach_btf_id(obj->btf_vmlinux,
+ mod_name ? fn_name : attach_name,
+ attach_type);
+ if (ret > 0) {
+ *btf_obj_fd = 0; /* vmlinux BTF */
+ *btf_type_id = ret;
+ return 0;
+ }
+ if (ret != -ENOENT)
+ return ret;
}
- if (ret != -ENOENT)
- return ret;
ret = load_module_btfs(obj);
if (ret)
@@ -9876,7 +9921,12 @@ static int find_kernel_btf_id(struct bpf_object *obj, const char *attach_name,
for (i = 0; i < obj->btf_module_cnt; i++) {
const struct module_btf *mod = &obj->btf_modules[i];
- ret = find_attach_btf_id(mod->btf, attach_name, attach_type);
+ if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0)
+ continue;
+
+ ret = find_attach_btf_id(mod->btf,
+ mod_name ? fn_name : attach_name,
+ attach_type);
if (ret > 0) {
*btf_obj_fd = mod->fd;
*btf_type_id = ret;
@@ -11380,13 +11430,14 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
struct kprobe_multi_resolve res = {
.pattern = pattern,
};
+ enum bpf_attach_type attach_type;
struct bpf_link *link = NULL;
char errmsg[STRERR_BUFSIZE];
const unsigned long *addrs;
int err, link_fd, prog_fd;
+ bool retprobe, session;
const __u64 *cookies;
const char **syms;
- bool retprobe;
size_t cnt;
if (!OPTS_VALID(opts, bpf_kprobe_multi_opts))
@@ -11425,6 +11476,12 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
}
retprobe = OPTS_GET(opts, retprobe, false);
+ session = OPTS_GET(opts, session, false);
+
+ if (retprobe && session)
+ return libbpf_err_ptr(-EINVAL);
+
+ attach_type = session ? BPF_TRACE_KPROBE_SESSION : BPF_TRACE_KPROBE_MULTI;
lopts.kprobe_multi.syms = syms;
lopts.kprobe_multi.addrs = addrs;
@@ -11439,7 +11496,7 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
}
link->detach = &bpf_link__detach_fd;
- link_fd = bpf_link_create(prog_fd, 0, BPF_TRACE_KPROBE_MULTI, &lopts);
+ link_fd = bpf_link_create(prog_fd, 0, attach_type, &lopts);
if (link_fd < 0) {
err = -errno;
pr_warn("prog '%s': failed to attach: %s\n",
@@ -11536,7 +11593,7 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru
n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
if (n < 1) {
- pr_warn("kprobe multi pattern is invalid: %s\n", pattern);
+ pr_warn("kprobe multi pattern is invalid: %s\n", spec);
return -EINVAL;
}
@@ -11545,6 +11602,32 @@ static int attach_kprobe_multi(const struct bpf_program *prog, long cookie, stru
return libbpf_get_error(*link);
}
+static int attach_kprobe_session(const struct bpf_program *prog, long cookie,
+ struct bpf_link **link)
+{
+ LIBBPF_OPTS(bpf_kprobe_multi_opts, opts, .session = true);
+ const char *spec;
+ char *pattern;
+ int n;
+
+ *link = NULL;
+
+ /* no auto-attach for SEC("kprobe.session") */
+ if (strcmp(prog->sec_name, "kprobe.session") == 0)
+ return 0;
+
+ spec = prog->sec_name + sizeof("kprobe.session/") - 1;
+ n = sscanf(spec, "%m[a-zA-Z0-9_.*?]", &pattern);
+ if (n < 1) {
+ pr_warn("kprobe session pattern is invalid: %s\n", spec);
+ return -EINVAL;
+ }
+
+ *link = bpf_program__attach_kprobe_multi_opts(prog, pattern, &opts);
+ free(pattern);
+ return *link ? 0 : -errno;
+}
+
static int attach_uprobe_multi(const struct bpf_program *prog, long cookie, struct bpf_link **link)
{
char *probe_type = NULL, *binary_path = NULL, *func_name = NULL;
generated by cgit (git 2.51.2) at 2025-11-30 15:05:05 +0000