From: Kenny Yu <kennyyu@fb.com>
Date: Mon, 24 Jan 2022 10:54:03 -0800
Subject: selftests/bpf: Add test for sleepable bpf iterator programs
Patch-mainline: v5.18-rc1
Git-commit: 45105c2eb751e2a3dd9858622cf72e2d588209a0
References: jsc#PED-1377
This adds a test for bpf iterator programs to make use of sleepable
bpf helpers.
Signed-off-by: Kenny Yu <kennyyu@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220124185403.468466-5-kennyyu@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/testing/selftests/bpf/prog_tests/bpf_iter.c | 20 ++++++++
tools/testing/selftests/bpf/progs/bpf_iter_task.c | 54 ++++++++++++++++++++++
2 files changed, 74 insertions(+)
--- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
@@ -138,6 +138,24 @@ static void test_task(void)
bpf_iter_task__destroy(skel);
}
+static void test_task_sleepable(void)
+{
+ struct bpf_iter_task *skel;
+
+ skel = bpf_iter_task__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "bpf_iter_task__open_and_load"))
+ return;
+
+ do_dummy_read(skel->progs.dump_task_sleepable);
+
+ ASSERT_GT(skel->bss->num_expected_failure_copy_from_user_task, 0,
+ "num_expected_failure_copy_from_user_task");
+ ASSERT_GT(skel->bss->num_success_copy_from_user_task, 0,
+ "num_success_copy_from_user_task");
+
+ bpf_iter_task__destroy(skel);
+}
+
static void test_task_stack(void)
{
struct bpf_iter_task_stack *skel;
@@ -1252,6 +1270,8 @@ void test_bpf_iter(void)
test_bpf_map();
if (test__start_subtest("task"))
test_task();
+ if (test__start_subtest("task_sleepable"))
+ test_task_sleepable();
if (test__start_subtest("task_stack"))
test_task_stack();
if (test__start_subtest("task_file"))
--- a/tools/testing/selftests/bpf/progs/bpf_iter_task.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
@@ -2,6 +2,7 @@
/* Copyright (c) 2020 Facebook */
#include "bpf_iter.h"
#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
@@ -23,3 +24,56 @@ int dump_task(struct bpf_iter__task *ctx
BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
return 0;
}
+
+int num_expected_failure_copy_from_user_task = 0;
+int num_success_copy_from_user_task = 0;
+
+SEC("iter.s/task")
+int dump_task_sleepable(struct bpf_iter__task *ctx)
+{
+ struct seq_file *seq = ctx->meta->seq;
+ struct task_struct *task = ctx->task;
+ static const char info[] = " === END ===";
+ struct pt_regs *regs;
+ void *ptr;
+ uint32_t user_data = 0;
+ int ret;
+
+ if (task == (void *)0) {
+ BPF_SEQ_PRINTF(seq, "%s\n", info);
+ return 0;
+ }
+
+ /* Read an invalid pointer and ensure we get an error */
+ ptr = NULL;
+ ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
+ if (ret) {
+ ++num_expected_failure_copy_from_user_task;
+ } else {
+ BPF_SEQ_PRINTF(seq, "%s\n", info);
+ return 0;
+ }
+
+ /* Try to read the contents of the task's instruction pointer from the
+ * remote task's address space.
+ */
+ regs = (struct pt_regs *)bpf_task_pt_regs(task);
+ if (regs == (void *)0) {
+ BPF_SEQ_PRINTF(seq, "%s\n", info);
+ return 0;
+ }
+ ptr = (void *)PT_REGS_IP(regs);
+
+ ret = bpf_copy_from_user_task(&user_data, sizeof(uint32_t), ptr, task, 0);
+ if (ret) {
+ BPF_SEQ_PRINTF(seq, "%s\n", info);
+ return 0;
+ }
+ ++num_success_copy_from_user_task;
+
+ if (ctx->meta->seq_num == 0)
+ BPF_SEQ_PRINTF(seq, " tgid gid data\n");
+
+ BPF_SEQ_PRINTF(seq, "%8d %8d %8d\n", task->tgid, task->pid, user_data);
+ return 0;
+}