Commit 45105c2e authored by Kenny Yu's avatar Kenny Yu Committed by Alexei Starovoitov
Browse files

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: default avatarKenny Yu <kennyyu@fb.com>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220124185403.468466-5-kennyyu@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent a8b77f74

tools/testing/selftests/bpf/prog_tests/bpf_iter.c

+20 −0
Original line number Diff line number Diff line
@@ -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"))

tools/testing/selftests/bpf/progs/bpf_iter_task.c

+54 −0
Original line number Diff line number Diff line
@@ -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;

}