On Thu, Jan 20, 2022 at 9:30 AM Kenny Yu <kennyyu@xxxxxx> wrote:
>
> This adds a test for bpf iterator programs to make use of sleepable
> bpf helpers.
>
> Signed-off-by: Kenny Yu <kennyyu@xxxxxx>
> ---
> .../selftests/bpf/prog_tests/bpf_iter.c | 19 ++++++++
> .../selftests/bpf/progs/bpf_iter_task.c | 47 +++++++++++++++++++
> 2 files changed, 66 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> index b84f859b1267..f6fb4f95513d 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c
> @@ -138,6 +138,23 @@ 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 (CHECK(!skel, "bpf_iter_task__open_and_load",
> + "skeleton open_and_load failed\n"))
Please use ASSERT_OK_PTR() instead.
> + return;
> +
> + do_dummy_read(skel->progs.dump_task_sleepable);
> +
> + ASSERT_GT(skel->bss->num_success_access_process_vm, 0,
> + "num_success_access_process_vm");
> +
> + bpf_iter_task__destroy(skel);
> +}
> +
> static void test_task_stack(void)
> {
> struct bpf_iter_task_stack *skel;
> @@ -1252,6 +1269,8 @@ 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 c86b93f33b32..3fa735af96f7 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 <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> @@ -23,3 +24,49 @@ int dump_task(struct bpf_iter__task *ctx)
> BPF_SEQ_PRINTF(seq, "%8d %8d\n", task->tgid, task->pid);
> return 0;
> }
> +
> +int num_success_access_process_vm = 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 numread;
> +
> + if (task == (void *)0) {
> + BPF_SEQ_PRINTF(seq, "%s\n", info);
> + return 0;
> + }
> +
> + 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);
> +
> + /* Try to read the contents of the task's instruction pointer from the
> + * remote task's address space.
> + */
> + numread = bpf_access_process_vm(&user_data,
> + sizeof(uint32_t),
> + ptr,
> + task,
> + 0);
nit: keep it on one line (up to 100 characters is ok)
> + if (numread != sizeof(uint32_t)) {
> + BPF_SEQ_PRINTF(seq, "%s\n", info);
> + return 0;
> + }
> + ++num_success_access_process_vm;
> +
> + 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;
> +}
> --
> 2.30.2
>
