Re: [PATCH v7 09/11] tools/testing/selftests/bpf: make it adopt to task comm size change

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Yafang Shao <laoar.shao@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
	Petr Mladek <pmladek@suse.com>,
	Peter Ziljstra <peterz@infradead.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Qiang Zhang <qiang.zhang@windriver.com>,
	robdclark <robdclark@chromium.org>,
	Christian Brauner <christian@brauner.io>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Martin Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	john fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	dennis.dalessandro@cornelisnetworks.com,
	mike.marciniszyn@cornelisnetworks.com,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	linux-rdma@vger.kernel.org, Networking <netdev@vger.kernel.org>,
	bpf <bpf@vger.kernel.org>,
	"linux-perf-use." <linux-perf-users@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org,
	Linux Memory Management List <linux-mm@kvack.org>,
	open list <linux-kernel@vger.kernel.org>,
	kernel test robot <oliver.sang@intel.com>,
	kbuild test robot <lkp@intel.com>
Subject: Re: [PATCH v7 09/11] tools/testing/selftests/bpf: make it adopt to task comm size change
Date: Mon, 1 Nov 2021 16:47:15 -0700	[thread overview]
Message-ID: <CAEf4BzafYdKmkJ_2sDMWibhWCZBPt=XLJwEAOgJDgnoYEvv4aA@mail.gmail.com> (raw)
In-Reply-To: <20211101060419.4682-10-laoar.shao@gmail.com>

On Sun, Oct 31, 2021 at 11:04 PM Yafang Shao <laoar.shao@gmail.com> wrote:
>
> The hard-coded 16 is used in various bpf progs. These progs get task
> comm either via bpf_get_current_comm() or prctl() or
> bpf_core_read_str(), all of which can work well even if the task comm size
> is changed.
>
> In these BPF programs, one thing to be improved is the
> sched:sched_switch tracepoint args. As the tracepoint args are derived
> from the kernel, we'd better make it same with the kernel. So the macro
> TASK_COMM_LEN is converted to type enum, then all the BPF programs can
> get it through BTF.
>
> The BPF program which wants to use TASK_COMM_LEN should include the header
> vmlinux.h. Regarding the test_stacktrace_map and test_tracepoint, as the
> type defined in linux/bpf.h are also defined in vmlinux.h, so we don't
> need to include linux/bpf.h again.
>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Petr Mladek <pmladek@suse.com>
> ---

LGTM, thanks.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

>  include/linux/sched.h                                   | 9 +++++++--
>  tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 6 +++---
>  tools/testing/selftests/bpf/progs/test_tracepoint.c     | 6 +++---
>  3 files changed, 13 insertions(+), 8 deletions(-)
>

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