From 45105c2eb751e2a3dd9858622cf72e2d588209a0 Mon Sep 17 00:00:00 2001 From: Kenny Yu Date: Mon, 24 Jan 2022 10:54:03 -0800 Subject: [PATCH] selftests/bpf: Add test for sleepable bpf iterator programs This adds a test for bpf iterator programs to make use of sleepable bpf helpers. Signed-off-by: Kenny Yu Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220124185403.468466-5-kennyyu@fb.com Signed-off-by: Alexei Starovoitov --- 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(+) diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index b84f859..5142a7d 100644 --- 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")) diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task.c b/tools/testing/selftests/bpf/progs/bpf_iter_task.c index c86b93f..d227412 100644 --- 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 +#include 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; +} -- 2.7.4