[PATCH v5 13/15] tools/testing/selftests/bpf: use TASK_COMM_LEN_16 instead of hard-coded 16

From: Yafang Shao
Date: Wed Oct 20 2021 - 23:47:42 EST

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.
Below is the detailed information,

bpf_get_current_comm:
progs/test_ringbuf.c
progs/test_ringbuf_multi.c

prctl:
prog_tests/test_overhead.c
prog_tests/trampoline_count.c

bpf_core_read_str:
progs/test_core_reloc_kernel.c
progs/test_sk_storage_tracing.c

We'd better replace the hard-coded 16 with TASK_COMM_LEN_16 to make it
more grepable.

Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
---
tools/testing/selftests/bpf/Makefile | 2 +-
tools/testing/selftests/bpf/prog_tests/ringbuf.c | 3 ++-
tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c | 3 ++-
.../testing/selftests/bpf/prog_tests/sk_storage_tracing.c | 3 ++-
tools/testing/selftests/bpf/prog_tests/test_overhead.c | 3 ++-
tools/testing/selftests/bpf/prog_tests/trampoline_count.c | 3 ++-
tools/testing/selftests/bpf/progs/profiler.h | 7 ++++---
tools/testing/selftests/bpf/progs/profiler.inc.h | 8 ++++----
tools/testing/selftests/bpf/progs/pyperf.h | 4 ++--
tools/testing/selftests/bpf/progs/strobemeta.h | 6 +++---
.../testing/selftests/bpf/progs/test_core_reloc_kernel.c | 3 ++-
tools/testing/selftests/bpf/progs/test_ringbuf.c | 3 ++-
tools/testing/selftests/bpf/progs/test_ringbuf_multi.c | 3 ++-
.../testing/selftests/bpf/progs/test_sk_storage_tracing.c | 5 +++--
tools/testing/selftests/bpf/progs/test_skb_helpers.c | 5 ++---
tools/testing/selftests/bpf/progs/test_stacktrace_map.c | 5 +++--
tools/testing/selftests/bpf/progs/test_tracepoint.c | 5 +++--
17 files changed, 41 insertions(+), 30 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 799b88152e9e..5e72d783d3fe 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -279,7 +279,7 @@ MENDIAN=$(if $(IS_LITTLE_ENDIAN),-mlittle-endian,-mbig-endian)

CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
BPF_CFLAGS = -g -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \
- -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) \
+ -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) -I${TOOLSINCDIR} \
-I$(abspath $(OUTPUT)/../usr/include)

CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 4706cee84360..ac82d57c09dc 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -12,6 +12,7 @@
#include <sys/sysinfo.h>
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
+#include <linux/sched/task.h>
#include "test_ringbuf.lskel.h"

#define EDONE 7777
@@ -22,7 +23,7 @@ struct sample {
int pid;
int seq;
long value;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

static int sample_cnt;
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
index 167cd8a2edfd..f0748305ffd6 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
@@ -2,6 +2,7 @@
#define _GNU_SOURCE
#include <test_progs.h>
#include <sys/epoll.h>
+#include <linux/sched/task.h>
#include "test_ringbuf_multi.skel.h"

static int duration = 0;
@@ -10,7 +11,7 @@ struct sample {
int pid;
int seq;
long value;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

static int process_sample(void *ctx, void *data, size_t len)
diff --git a/tools/testing/selftests/bpf/prog_tests/sk_storage_tracing.c b/tools/testing/selftests/bpf/prog_tests/sk_storage_tracing.c
index 2b392590e8ca..f77d3b44ed35 100644
--- a/tools/testing/selftests/bpf/prog_tests/sk_storage_tracing.c
+++ b/tools/testing/selftests/bpf/prog_tests/sk_storage_tracing.c
@@ -4,6 +4,7 @@
#include <sys/types.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
+#include <linux/sched/task.h>
#include "test_progs.h"
#include "network_helpers.h"
#include "test_sk_storage_trace_itself.skel.h"
@@ -15,7 +16,7 @@
struct sk_stg {
__u32 pid;
__u32 last_notclose_state;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

static struct test_sk_storage_tracing *skel;
diff --git a/tools/testing/selftests/bpf/prog_tests/test_overhead.c b/tools/testing/selftests/bpf/prog_tests/test_overhead.c
index 123c68c1917d..133987217f57 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_overhead.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_overhead.c
@@ -4,6 +4,7 @@
#include <sched.h>
#include <sys/prctl.h>
#include <test_progs.h>
+#include <linux/sched/task.h>

#define MAX_CNT 100000

@@ -67,7 +68,7 @@ void test_test_overhead(void)
struct bpf_object *obj;
struct bpf_link *link;
int err, duration = 0;
- char comm[16] = {};
+ char comm[TASK_COMM_LEN_16] = {};

if (CHECK_FAIL(prctl(PR_GET_NAME, comm, 0L, 0L, 0L)))
return;
diff --git a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
index d7f5a931d7f3..4765b2ebd219 100644
--- a/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
+++ b/tools/testing/selftests/bpf/prog_tests/trampoline_count.c
@@ -3,6 +3,7 @@
#include <sched.h>
#include <sys/prctl.h>
#include <test_progs.h>
+#include <linux/sched/task.h>

#define MAX_TRAMP_PROGS 38

@@ -50,7 +51,7 @@ void test_trampoline_count(void)
int err, i = 0, duration = 0;
struct bpf_object *obj;
struct bpf_link *link;
- char comm[16] = {};
+ char comm[TASK_COMM_LEN_16] = {};

/* attach 'allowed' trampoline programs */
for (i = 0; i < MAX_TRAMP_PROGS; i++) {
diff --git a/tools/testing/selftests/bpf/progs/profiler.h b/tools/testing/selftests/bpf/progs/profiler.h
index 3bac4fdd4bdf..7ffc801d790b 100644
--- a/tools/testing/selftests/bpf/progs/profiler.h
+++ b/tools/testing/selftests/bpf/progs/profiler.h
@@ -2,7 +2,8 @@
/* Copyright (c) 2020 Facebook */
#pragma once

-#define TASK_COMM_LEN 16
+#include <linux/sched/task.h>
+
#define MAX_ANCESTORS 4
#define MAX_PATH 256
#define KILL_TARGET_LEN 64
@@ -14,7 +15,7 @@
#define MAX_FILEPATH_LENGTH (MAX_PATH_DEPTH * MAX_PATH)
#define MAX_CGROUPS_PATH_DEPTH 8

-#define MAX_METADATA_PAYLOAD_LEN TASK_COMM_LEN
+#define MAX_METADATA_PAYLOAD_LEN TASK_COMM_LEN_16

#define MAX_CGROUP_PAYLOAD_LEN \
(MAX_PATH * 2 + (MAX_PATH * MAX_CGROUPS_PATH_DEPTH))
@@ -25,7 +26,7 @@
(MAX_METADATA_PAYLOAD_LEN + MAX_CGROUP_PAYLOAD_LEN + CTL_MAXNAME + MAX_PATH)

#define MAX_KILL_PAYLOAD_LEN \
- (MAX_METADATA_PAYLOAD_LEN + MAX_CGROUP_PAYLOAD_LEN + TASK_COMM_LEN + \
+ (MAX_METADATA_PAYLOAD_LEN + MAX_CGROUP_PAYLOAD_LEN + TASK_COMM_LEN_16 + \
KILL_TARGET_LEN)

#define MAX_EXEC_PAYLOAD_LEN \
diff --git a/tools/testing/selftests/bpf/progs/profiler.inc.h b/tools/testing/selftests/bpf/progs/profiler.inc.h
index 4896fdf816f7..fad39075e5ce 100644
--- a/tools/testing/selftests/bpf/progs/profiler.inc.h
+++ b/tools/testing/selftests/bpf/progs/profiler.inc.h
@@ -344,9 +344,9 @@ static INLINE void* populate_var_metadata(struct var_metadata_t* metadata,
metadata->start_time = BPF_CORE_READ(task, start_time);
metadata->comm_length = 0;

- size_t comm_length = bpf_core_read_str(payload, TASK_COMM_LEN, &task->comm);
+ size_t comm_length = bpf_core_read_str(payload, TASK_COMM_LEN_16, &task->comm);
barrier_var(comm_length);
- if (comm_length <= TASK_COMM_LEN) {
+ if (comm_length <= TASK_COMM_LEN_16) {
barrier_var(comm_length);
metadata->comm_length = comm_length;
payload += comm_length;
@@ -648,9 +648,9 @@ int raw_tracepoint__sched_process_exit(void* ctx)
kill_data->kill_target_name_length = 0;
kill_data->kill_target_cgroup_proc_length = 0;

- size_t comm_length = bpf_core_read_str(payload, TASK_COMM_LEN, &task->comm);
+ size_t comm_length = bpf_core_read_str(payload, TASK_COMM_LEN_16, &task->comm);
barrier_var(comm_length);
- if (comm_length <= TASK_COMM_LEN) {
+ if (comm_length <= TASK_COMM_LEN_16) {
barrier_var(comm_length);
kill_data->kill_target_name_length = comm_length;
payload += comm_length;
diff --git a/tools/testing/selftests/bpf/progs/pyperf.h b/tools/testing/selftests/bpf/progs/pyperf.h
index 2fb7adafb6b6..05cb40268887 100644
--- a/tools/testing/selftests/bpf/progs/pyperf.h
+++ b/tools/testing/selftests/bpf/progs/pyperf.h
@@ -6,11 +6,11 @@
#include <stddef.h>
#include <stdbool.h>
#include <linux/bpf.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>

#define FUNCTION_NAME_LEN 64
#define FILE_NAME_LEN 128
-#define TASK_COMM_LEN 16

typedef struct {
int PyThreadState_frame;
@@ -43,7 +43,7 @@ typedef struct {
typedef struct {
uint32_t pid;
uint32_t tid;
- char comm[TASK_COMM_LEN];
+ char comm[TASK_COMM_LEN_16];
int32_t kernel_stack_id;
int32_t user_stack_id;
bool thread_current;
diff --git a/tools/testing/selftests/bpf/progs/strobemeta.h b/tools/testing/selftests/bpf/progs/strobemeta.h
index 7de534f38c3f..acfe929fd32d 100644
--- a/tools/testing/selftests/bpf/progs/strobemeta.h
+++ b/tools/testing/selftests/bpf/progs/strobemeta.h
@@ -8,12 +8,12 @@
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/types.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>

typedef uint32_t pid_t;
struct task_struct {};

-#define TASK_COMM_LEN 16
#define PERF_MAX_STACK_DEPTH 127

#define STROBE_TYPE_INVALID 0
@@ -189,7 +189,7 @@ struct strobemeta_payload {

struct strobelight_bpf_sample {
uint64_t ktime;
- char comm[TASK_COMM_LEN];
+ char comm[TASK_COMM_LEN_16];
pid_t pid;
int user_stack_id;
int kernel_stack_id;
@@ -520,7 +520,7 @@ int on_event(struct pt_regs *ctx) {
return 0; /* this will never happen */

sample->pid = pid;
- bpf_get_current_comm(&sample->comm, TASK_COMM_LEN);
+ bpf_get_current_comm(&sample->comm, TASK_COMM_LEN_16);
ktime_ns = bpf_ktime_get_ns();
sample->ktime = ktime_ns;

diff --git a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
index 145028b52ad8..33bf5b1058e5 100644
--- a/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
+++ b/tools/testing/selftests/bpf/progs/test_core_reloc_kernel.c
@@ -4,6 +4,7 @@
#include <linux/bpf.h>
#include <stdint.h>
#include <stdbool.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>

@@ -26,7 +27,7 @@ struct core_reloc_kernel_output {
struct task_struct {
int pid;
int tgid;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
struct task_struct *group_leader;
};

diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf.c b/tools/testing/selftests/bpf/progs/test_ringbuf.c
index eaa7d9dba0be..15bb2087371e 100644
--- a/tools/testing/selftests/bpf/progs/test_ringbuf.c
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf.c
@@ -2,6 +2,7 @@
// Copyright (c) 2020 Facebook

#include <linux/bpf.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>

char _license[] SEC("license") = "GPL";
@@ -10,7 +11,7 @@ struct sample {
int pid;
int seq;
long value;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

struct {
diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
index 197b86546dca..88c7f65a8f3f 100644
--- a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
@@ -2,6 +2,7 @@
// Copyright (c) 2020 Facebook

#include <linux/bpf.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>

char _license[] SEC("license") = "GPL";
@@ -10,7 +11,7 @@ struct sample {
int pid;
int seq;
long value;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

struct ringbuf_map {
diff --git a/tools/testing/selftests/bpf/progs/test_sk_storage_tracing.c b/tools/testing/selftests/bpf/progs/test_sk_storage_tracing.c
index 8e94e5c080aa..cd965e9f22f0 100644
--- a/tools/testing/selftests/bpf/progs/test_sk_storage_tracing.c
+++ b/tools/testing/selftests/bpf/progs/test_sk_storage_tracing.c
@@ -2,6 +2,7 @@
/* Copyright (c) 2020 Facebook */

#include <vmlinux.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
#include <bpf/bpf_helpers.h>
@@ -9,7 +10,7 @@
struct sk_stg {
__u32 pid;
__u32 last_notclose_state;
- char comm[16];
+ char comm[TASK_COMM_LEN_16];
};

struct {
@@ -27,7 +28,7 @@ struct {
__type(value, int);
} del_sk_stg_map SEC(".maps");

-char task_comm[16] = "";
+char task_comm[TASK_COMM_LEN_16] = "";

SEC("tp_btf/inet_sock_set_state")
int BPF_PROG(trace_inet_sock_set_state, struct sock *sk, int oldstate,
diff --git a/tools/testing/selftests/bpf/progs/test_skb_helpers.c b/tools/testing/selftests/bpf/progs/test_skb_helpers.c
index bb3fbf1a29e3..cbe134eab8fe 100644
--- a/tools/testing/selftests/bpf/progs/test_skb_helpers.c
+++ b/tools/testing/selftests/bpf/progs/test_skb_helpers.c
@@ -1,10 +1,9 @@
// SPDX-License-Identifier: GPL-2.0-only
#include "vmlinux.h"
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>

-#define TEST_COMM_LEN 16
-
struct {
__uint(type, BPF_MAP_TYPE_CGROUP_ARRAY);
__uint(max_entries, 1);
@@ -18,7 +17,7 @@ SEC("classifier/test_skb_helpers")
int test_skb_helpers(struct __sk_buff *skb)
{
struct task_struct *task;
- char comm[TEST_COMM_LEN];
+ char comm[TASK_COMM_LEN_16];
__u32 tpid;

task = (struct task_struct *)bpf_get_current_task();
diff --git a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
index 00ed48672620..e4938b3cdf7a 100644
--- a/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
+++ b/tools/testing/selftests/bpf/progs/test_stacktrace_map.c
@@ -2,6 +2,7 @@
// Copyright (c) 2018 Facebook

#include <linux/bpf.h>
+#include <linux/sched/task.h>
#include <bpf/bpf_helpers.h>

#ifndef PERF_MAX_STACK_DEPTH
@@ -41,11 +42,11 @@ 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_16];
int prev_pid;
int prev_prio;
long long prev_state;
- char next_comm[16];
+ char next_comm[TASK_COMM_LEN_16];
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..eb6e84ebf704 100644
--- a/tools/testing/selftests/bpf/progs/test_tracepoint.c
+++ b/tools/testing/selftests/bpf/progs/test_tracepoint.c
@@ -2,16 +2,17 @@
// Copyright (c) 2017 Facebook

#include <linux/bpf.h>
+#include <linux/sched/task.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_16];
int prev_pid;
int prev_prio;
long long prev_state;
- char next_comm[16];
+ char next_comm[TASK_COMM_LEN_16];
int next_pid;
int next_prio;
};
--
2.17.1