From: Jackie Liu <liu.yun@linux.dev>
To: Jiri Olsa <olsajiri@gmail.com>
Cc: andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yhs@fb.com, bpf@vger.kernel.org, liuyun01@kylinos.cn
Subject: Re: [PATCH v5] libbpf: kprobe.multi: Filter with available_filter_functions
Date: Fri, 26 May 2023 20:18:45 +0800 [thread overview]
Message-ID: <4365dadc-05f3-c0ea-3318-3c55cef177be@linux.dev> (raw)
In-Reply-To: <ZHCBfW6AAxCO53mC@krava>
在 2023/5/26 17:53, Jiri Olsa 写道:
> 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
It is necessary to set cap to 0, cnt is already 0, if syms exists.
>
>> +}
>> +
>> 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
Yes.
>
> 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
>>
next prev parent reply other threads:[~2023-05-26 12:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-23 13:25 [PATCH] libbpf: kprobe.multi: Filter with blacklist and available_filter_functions Jackie Liu
2023-05-23 16:17 ` Jiri Olsa
2023-05-23 18:22 ` Andrii Nakryiko
2023-05-24 7:03 ` Jiri Olsa
2023-05-24 1:03 ` Jackie Liu
2023-05-24 1:19 ` Jackie Liu
2023-05-24 6:47 ` Jiri Olsa
2023-05-24 7:06 ` Jackie Liu
2023-05-24 8:41 ` [PATCH v3] libbpf: kprobe.multi: Filter with available_filter_functions Jackie Liu
2023-05-25 8:44 ` Jiri Olsa
2023-05-25 10:27 ` [PATCH v4] " Jackie Liu
2023-05-25 20:43 ` Andrii Nakryiko
2023-05-26 1:38 ` Jackie Liu
2023-05-26 8:58 ` Jiri Olsa
2023-06-02 17:27 ` Andrii Nakryiko
2023-06-07 6:01 ` Jackie Liu
2023-06-07 22:37 ` Andrii Nakryiko
2023-06-07 23:22 ` Jiri Olsa
2023-06-08 0:00 ` Andrii Nakryiko
2023-06-08 0:57 ` Jackie Liu
2023-05-26 2:10 ` [PATCH v5] " Jackie Liu
2023-05-26 9:53 ` Jiri Olsa
2023-05-26 12:18 ` Jackie Liu [this message]
2023-05-24 3:44 ` [PATCH v2] " Jackie Liu
2023-05-26 12:20 [PATCH v5] " Jackie Liu
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