On Fri, May 26, 2023 at 10:10:47AM +0800, Jackie Liu wrote:
SNIP
> -resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
> - const char *sym_name, void *ctx)
> +kallsyms_resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
> + const char *sym_name, void *ctx)
> {
> struct kprobe_multi_resolve *res = ctx;
> int err;
> @@ -10431,8 +10438,8 @@ resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
> if (!glob_match(sym_name, res->pattern))
> return 0;
>
> - err = libbpf_ensure_mem((void **) &res->addrs, &res->cap, sizeof(unsigned long),
> - res->cnt + 1);
> + err = libbpf_ensure_mem((void **) &res->addrs, &res->cap,
> + sizeof(unsigned long), res->cnt + 1);
hum, looks like this is just formatting change, AFAICS we don't need that
> if (err)
> return err;
>
> @@ -10440,6 +10447,75 @@ resolve_kprobe_multi_cb(unsigned long long sym_addr, char sym_type,
> return 0;
> }
>
SNIP
> +
> +static void kprobe_multi_resolve_free(struct kprobe_multi_resolve *res)
> +{
> + while (res->syms && res->cnt)
> + free((char *)res->syms[--res->cnt]);
> +
> + free(res->syms);
> + free(res->addrs);
we should set cnt and cap to zero for the fallback sake
> +}
> +
> struct bpf_link *
> bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> const char *pattern,
> @@ -10476,13 +10552,20 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> return libbpf_err_ptr(-EINVAL);
>
> if (pattern) {
> - err = libbpf_kallsyms_parse(resolve_kprobe_multi_cb, &res);
> - if (err)
> - goto error;
> + err = libbpf_available_kprobes_parse(ftrace_resolve_kprobe_multi_cb,
> + &res);
> + if (err) {
> + /* fallback to kallsyms */
we need to call kprobe_multi_resolve_free in here and set
cnt/cap to zero in kprobe_multi_resolve_free
jirka
> + err = libbpf_kallsyms_parse(kallsyms_resolve_kprobe_multi_cb,
> + &res);
> + if (err)
> + goto error;
> + }
> if (!res.cnt) {
> err = -ENOENT;
> goto error;
> }
> + syms = res.syms;
> addrs = res.addrs;
> cnt = res.cnt;
> }
> @@ -10511,12 +10594,12 @@ bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog,
> goto error;
> }
> link->fd = link_fd;
> - free(res.addrs);
> + kprobe_multi_resolve_free(&res);
> return link;
>
> error:
> free(link);
> - free(res.addrs);
> + kprobe_multi_resolve_free(&res);
> return libbpf_err_ptr(err);
> }
>
> --
> 2.25.1
>
