From: Yafang Shao <laoar.shao@gmail.com>
To: akpm@linux-foundation.org, keescook@chromium.org,
rostedt@goodmis.org, mathieu.desnoyers@efficios.com,
arnaldo.melo@gmail.com, pmladek@suse.com, peterz@infradead.org,
viro@zeniv.linux.org.uk, valentin.schneider@arm.com,
qiang.zhang@windriver.com, robdclark@chromium.org,
christian@brauner.io, dietmar.eggemann@arm.com, mingo@redhat.com,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
davem@davemloft.net, kuba@kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, kafai@fb.com,
songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com,
kpsingh@kernel.org, dennis.dalessandro@cornelisnetworks.com,
mike.marciniszyn@cornelisnetworks.com, dledford@redhat.com,
jgg@ziepe.ca
Cc: linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, linux-perf-users@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, oliver.sang@intel.com,
lkp@intel.com, Yafang Shao <laoar.shao@gmail.com>,
Andrii Nakryiko <andrii.nakryiko@gmail.com>
Subject: [PATCH v7 09/11] tools/testing/selftests/bpf: make it adopt to task comm size change
Date: Mon, 1 Nov 2021 06:04:17 +0000 [thread overview]
Message-ID: <20211101060419.4682-10-laoar.shao@gmail.com> (raw)
In-Reply-To: <20211101060419.4682-1-laoar.shao@gmail.com>
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>
---
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(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b9c85c52fed0..09ac13e54549 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -274,8 +274,13 @@ struct task_group;
#define get_current_state() READ_ONCE(current->__state)
-/* Task command name length: */
-#define TASK_COMM_LEN 16
+/*
+ * Define the task command name length as enum, then it can be visible to
+ * BPF programs.
+ */
+enum {
+ TASK_COMM_LEN = 16,
+};
extern void scheduler_tick(void);
diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
index 00ed48672620..e9b602a6dc1b 100644
--- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
+++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
@@ -1,7 +1,7 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
-#include <linux/bpf.h>
+#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#ifndef PERF_MAX_STACK_DEPTH
@@ -41,11 +41,11 @@ struct {
/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
struct sched_switch_args {
unsigned long long pad;
- char prev_comm[16];
+ char prev_comm[TASK_COMM_LEN];
int prev_pid;
int prev_prio;
long long prev_state;
- char next_comm[16];
+ char next_comm[TASK_COMM_LEN];
int next_pid;
int next_prio;
};
diff --git a/tools/testing/selftests/bpf/progs/test_tracepoint.c b/tools/testing/selftests/bpf/progs/test_tracepoint.c
index 4b825ee122cf..f21982681e28 100644
--- a/tools/testing/selftests/bpf/progs/test_tracepoint.c
+++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c
@@ -1,17 +1,17 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017 Facebook
-#include <linux/bpf.h>
+#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
struct sched_switch_args {
unsigned long long pad;
- char prev_comm[16];
+ char prev_comm[TASK_COMM_LEN];
int prev_pid;
int prev_prio;
long long prev_state;
- char next_comm[16];
+ char next_comm[TASK_COMM_LEN];
int next_pid;
int next_prio;
};
--
2.17.1
next prev parent reply other threads:[~2021-11-01 6:05 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 6:04 [PATCH v7 00/11] extend task comm from 16 to 24 Yafang Shao
2021-11-01 6:04 ` [PATCH v7 01/11] fs/exec: make __set_task_comm always set a nul terminated string Yafang Shao
2021-11-01 6:04 ` [PATCH v7 02/11] fs/exec: make __get_task_comm always get " Yafang Shao
2021-11-01 6:04 ` [PATCH v7 03/11] sched.h: use __must_be_array instead of BUILD_BUG_ON in get_task_comm Yafang Shao
2021-11-01 6:04 ` [PATCH v7 04/11] drivers/infiniband: make setup_ctxt always get a nul terminated task comm Yafang Shao
2021-11-01 6:04 ` [PATCH v7 05/11] fs/binfmt_elf: make prpsinfo " Yafang Shao
2021-11-01 6:04 ` [PATCH v7 06/11] samples/bpf/test_overhead_kprobe_kern: make it adopt to task comm size change Yafang Shao
2021-11-01 6:04 ` [PATCH v7 07/11] tools/bpf/bpftool/skeleton: " Yafang Shao
2021-11-01 23:47 ` Andrii Nakryiko
2021-11-01 6:04 ` [PATCH v7 08/11] tools/perf/test: make perf test " Yafang Shao
2021-11-17 14:31 ` Arnaldo Carvalho de Melo
2021-11-18 14:18 ` Yafang Shao
2021-11-01 6:04 ` Yafang Shao [this message]
2021-11-01 23:47 ` [PATCH v7 09/11] tools/testing/selftests/bpf: make it " Andrii Nakryiko
2021-11-01 6:04 ` [PATCH v7 10/11] sched.h: extend task comm from 16 to 24 Yafang Shao
2021-11-01 6:04 ` [PATCH v7 11/11] kernel/kthread: show a warning if kthread's comm is truncated Yafang Shao
2021-11-01 12:44 ` [PATCH v7 00/11] extend task comm from 16 to 24 Matthew Wilcox
2021-11-01 13:12 ` Yafang Shao
2021-11-01 14:07 ` Petr Mladek
2021-11-01 14:34 ` Yafang Shao
2021-11-01 16:02 ` Petr Mladek
2021-11-01 16:06 ` Steven Rostedt
2021-11-02 1:09 ` Yafang Shao
2021-11-02 1:18 ` Steven Rostedt
2021-11-02 1:26 ` Yafang Shao
2021-11-02 7:56 ` Petr Mladek
2021-11-02 13:48 ` Yafang Shao
2021-11-02 9:26 ` David Hildenbrand
2021-11-04 1:37 ` Michał Mirosław
2021-11-05 6:34 ` Yafang Shao
2021-11-05 23:57 ` Michał Mirosław
2021-11-06 9:12 ` Yafang Shao
2021-11-06 11:29 ` Michał Mirosław
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