From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Feng Yang <yangfeng59949@163.com>
Cc: alexei.starovoitov@gmail.com, andrii@kernel.org, ast@kernel.org,
bpf@vger.kernel.org, daniel@iogearbox.net, eddyz87@gmail.com,
haoluo@google.com, john.fastabend@gmail.com, jolsa@kernel.org,
kpsingh@kernel.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, martin.lau@linux.dev,
sdf@fomichev.me, song@kernel.org, yonghong.song@linux.dev
Subject: Re: [BUG] Failed to obtain stack trace via bpf_get_stackid on ARM64 architecture
Date: Wed, 24 Sep 2025 17:04:16 +0900 [thread overview]
Message-ID: <20250924170416.0874e56c2ce99a4de92e05b8@kernel.org> (raw)
In-Reply-To: <20250924062536.471231-1-yangfeng59949@163.com>
On Wed, 24 Sep 2025 14:25:36 +0800
Feng Yang <yangfeng59949@163.com> wrote:
> By the way, during my testing, I also noticed that when executing bpf_get_stackid via kprobes or tracepoints,
> the command bpftrace -e 'kprobe:bpf_get_stackid {printf("bpf_get_stackid\n");}' produces no output.
I think this is because the bpf_get_stackid is a kind of recursive
event from kprobes. Kprobe handler can not be reentered.
> However, it does output something when bpf_get_stackid is invoked via uprobes.
> This phenomenon also occurs on the x86 architecture, could this be a bug as well?
Maybe if bpf_get_stackid() is kicked from uprobes, it is not recursive
call from kprobes, so it works.
So it is expected behavior, not a bug. Sorry for confusion.
Thank you,
>
> Thanks.
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2025-09-24 8:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-19 7:19 [BUG] Failed to obtain stack trace via bpf_get_stackid on ARM64 architecture Feng Yang
2025-09-20 2:56 ` Alexei Starovoitov
2025-09-20 22:17 ` Jiri Olsa
2025-09-21 13:30 ` Masami Hiramatsu
2025-09-22 2:15 ` Feng Yang
2025-09-23 15:32 ` Masami Hiramatsu
2025-09-24 6:25 ` Feng Yang
2025-09-24 7:31 ` Masami Hiramatsu
2025-09-24 8:04 ` Masami Hiramatsu [this message]
2025-09-24 10:53 ` Feng Yang
2025-09-24 22:00 ` Masami Hiramatsu
2025-09-24 15:42 ` Jiri Olsa
2025-09-24 21:56 ` Masami Hiramatsu
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