Re: [PATCH v7 07/11] tools/bpf/bpftool/skeleton: make it adopt to task comm size change

From: Andrii Nakryiko
Date: Mon Nov 01 2021 - 19:47:59 EST


On Sun, Oct 31, 2021 at 11:04 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
> we don't care about if the dst size is big enough.
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx>
> Cc: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
> Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Petr Mladek <pmladek@xxxxxxxx>
> ---

LGTM.

Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>

> tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
> index d9b420972934..f70702fcb224 100644
> --- a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
> +++ b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c
> @@ -71,8 +71,8 @@ int iter(struct bpf_iter__task_file *ctx)
>
> e.pid = task->tgid;
> e.id = get_obj_id(file->private_data, obj_type);
> - bpf_probe_read_kernel(&e.comm, sizeof(e.comm),
> - task->group_leader->comm);
> + bpf_probe_read_kernel_str(&e.comm, sizeof(e.comm),
> + task->group_leader->comm);
> bpf_seq_write(ctx->meta->seq, &e, sizeof(e));
>
> return 0;
> --
> 2.17.1
>