From: Jiri Olsa <olsajiri@gmail.com>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, kernel-team@meta.com
Subject: Re: [PATCH bpf 2/5] bpf: remove unnecessary rcu_read_{lock,unlock}() in multi-uprobe attach logic
Date: Tue, 21 May 2024 12:04:55 +0200 [thread overview]
Message-ID: <Zkxxx065g7Kg0Vl2@krava> (raw)
In-Reply-To: <20240520234720.1748918-3-andrii@kernel.org>
On Mon, May 20, 2024 at 04:47:17PM -0700, Andrii Nakryiko wrote:
> get_pid_task() internally already calls rcu_read_lock() and
> rcu_read_unlock(), so there is no point to do this one extra time.
>
> This is a drive-by improvements and has no correctness implications.
>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
jirka
> ---
> kernel/trace/bpf_trace.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 1baaeb9ca205..6249dac61701 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3423,9 +3423,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> }
>
> if (pid) {
> - rcu_read_lock();
> task = get_pid_task(find_vpid(pid), PIDTYPE_TGID);
> - rcu_read_unlock();
> if (!task) {
> err = -ESRCH;
> goto error_path_put;
> --
> 2.43.0
>
>
next prev parent reply other threads:[~2024-05-21 10:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-20 23:47 [PATCH bpf 0/5] Fix BPF multi-uprobe PID filtering logic Andrii Nakryiko
2024-05-20 23:47 ` [PATCH bpf 1/5] bpf: fix " Andrii Nakryiko
2024-05-21 10:04 ` Jiri Olsa
2024-05-20 23:47 ` [PATCH bpf 2/5] bpf: remove unnecessary rcu_read_{lock,unlock}() in multi-uprobe attach logic Andrii Nakryiko
2024-05-21 10:04 ` Jiri Olsa [this message]
2024-05-20 23:47 ` [PATCH bpf 3/5] libbpf: detect broken PID filtering logic for multi-uprobe Andrii Nakryiko
2024-05-21 10:04 ` Jiri Olsa
2024-05-21 16:12 ` Andrii Nakryiko
2024-05-20 23:47 ` [PATCH bpf 4/5] selftests/bpf: extend multi-uprobe tests with child thread case Andrii Nakryiko
2024-05-20 23:47 ` [PATCH bpf 5/5] selftests/bpf: extend multi-uprobe tests with USDTs Andrii Nakryiko
2024-05-21 4:54 ` Andrii Nakryiko
2024-05-21 5:05 ` Alexei Starovoitov
2024-05-21 10:04 ` Jiri Olsa
2024-05-21 16:13 ` Andrii Nakryiko
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