From: Daniel Borkmann <daniel@iogearbox.net>
To: Song Liu <songliubraving@fb.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: ast@kernel.org, kernel-team@fb.com, john.fastabend@gmail.com,
kpsingh@chromium.org
Subject: Re: [PATCH bpf-next 1/3] bpf: introduce helper bpf_get_task_stack_trace()
Date: Tue, 23 Jun 2020 17:22:36 +0200 [thread overview]
Message-ID: <a50decc5-df68-0b6d-3449-41c5fb07330a@iogearbox.net> (raw)
In-Reply-To: <20200623070802.2310018-2-songliubraving@fb.com>
On 6/23/20 9:08 AM, Song Liu wrote:
> This helper can be used with bpf_iter__task to dump all /proc/*/stack to
> a seq_file.
>
> Signed-off-by: Song Liu <songliubraving@fb.com>
> ---
> include/uapi/linux/bpf.h | 10 +++++++++-
> kernel/trace/bpf_trace.c | 21 +++++++++++++++++++++
> scripts/bpf_helpers_doc.py | 2 ++
> tools/include/uapi/linux/bpf.h | 10 +++++++++-
> 4 files changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 19684813faaed..a30416b822fe3 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3252,6 +3252,13 @@ union bpf_attr {
> * case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
> * is returned or the error code -EACCES in case the skb is not
> * subject to CHECKSUM_UNNECESSARY.
> + *
> + * int bpf_get_task_stack_trace(struct task_struct *task, void *entries, u32 size)
> + * Description
> + * Save a task stack trace into array *entries*. This is a wrapper
> + * over stack_trace_save_tsk().
> + * Return
> + * Number of trace entries stored.
> */
> #define __BPF_FUNC_MAPPER(FN) \
> FN(unspec), \
> @@ -3389,7 +3396,8 @@ union bpf_attr {
> FN(ringbuf_submit), \
> FN(ringbuf_discard), \
> FN(ringbuf_query), \
> - FN(csum_level),
> + FN(csum_level), \
> + FN(get_task_stack_trace),
>
> /* integer value in 'imm' field of BPF_CALL instruction selects which helper
> * function eBPF program intends to call
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index e729c9e587a07..2c13bcb5c2bce 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -1488,6 +1488,23 @@ static const struct bpf_func_proto bpf_get_stack_proto_raw_tp = {
> .arg4_type = ARG_ANYTHING,
> };
>
> +BPF_CALL_3(bpf_get_task_stack_trace, struct task_struct *, task,
> + void *, entries, u32, size)
> +{
> + return stack_trace_save_tsk(task, (unsigned long *)entries, size, 0);
nit: cast not needed.
> +}
> +
> +static int bpf_get_task_stack_trace_btf_ids[5];
> +static const struct bpf_func_proto bpf_get_task_stack_trace_proto = {
> + .func = bpf_get_task_stack_trace,
> + .gpl_only = true,
> + .ret_type = RET_INTEGER,
> + .arg1_type = ARG_PTR_TO_BTF_ID,
> + .arg2_type = ARG_PTR_TO_MEM,
> + .arg3_type = ARG_CONST_SIZE_OR_ZERO,
Is there a use-case to pass in entries == NULL + size == 0?
> + .btf_id = bpf_get_task_stack_trace_btf_ids,
> +};
> +
next prev parent reply other threads:[~2020-06-23 15:25 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 7:07 [PATCH bpf-next 0/3] bpf: introduce bpf_get_task_stack_trace() Song Liu
2020-06-23 7:08 ` [PATCH bpf-next 1/3] bpf: introduce helper bpf_get_task_stack_trace() Song Liu
2020-06-23 15:19 ` Alexei Starovoitov
2020-06-23 16:59 ` Song Liu
2020-06-23 17:40 ` Song Liu
2020-06-23 18:41 ` Andrii Nakryiko
2020-06-23 15:22 ` Daniel Borkmann [this message]
2020-06-23 17:19 ` Song Liu
2020-06-23 18:45 ` Andrii Nakryiko
2020-06-23 22:53 ` Song Liu
2020-06-23 7:08 ` [PATCH bpf-next 2/3] bpf: allow %pB in bpf_seq_printf() Song Liu
2020-06-23 15:29 ` Daniel Borkmann
2020-06-23 17:19 ` Song Liu
2020-06-23 7:08 ` [PATCH bpf-next 3/3] selftests/bpf: add bpf_iter test with bpf_get_task_stack_trace() Song Liu
2020-06-23 18:57 ` Yonghong Song
2020-06-23 22:07 ` Song Liu
2020-06-23 22:27 ` Yonghong Song
2020-06-24 20:37 ` Song Liu
2020-06-25 5:29 ` Yonghong Song
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