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

From: Yafang Shao <hidden>
Date: 2021-10-21 03:47:39
Also in: bpf, linux-fsdevel, linux-perf-users, lkml
Subsystem: bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds

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 <redacted>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <redacted>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kees Cook <redacted>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
---
 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;
 };

-- 
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