On Mon, Feb 5, 2024 at 7:02 AM Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx> wrote:
>
> Add selftests covering the following cases:
> - A static subprog called from within a RCU read section works
> - A static subprog taking an RCU read lock which is released in caller works
> - A static subprog releasing the caller's RCU read lock works
Given the global subprog is not allowed, we'd better add failure
cases for a global subprog.
>
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/rcu_read_lock.c | 3 +
> .../selftests/bpf/progs/rcu_read_lock.c | 64 +++++++++++++++++++
> 2 files changed, 67 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c
> index 3f1f58d3a729..328a25e031d8 100644
> --- a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c
> +++ b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c
> @@ -29,6 +29,9 @@ static void test_success(void)
> bpf_program__set_autoload(skel->progs.non_sleepable_1, true);
> bpf_program__set_autoload(skel->progs.non_sleepable_2, true);
> bpf_program__set_autoload(skel->progs.task_trusted_non_rcuptr, true);
> + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog, true);
> + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog_lock, true);
> + bpf_program__set_autoload(skel->progs.rcu_read_lock_subprog_unlock, true);
> err = rcu_read_lock__load(skel);
> if (!ASSERT_OK(err, "skel_load"))
> goto out;
> diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c
> index 14fb01437fb8..687df026feb0 100644
> --- a/tools/testing/selftests/bpf/progs/rcu_read_lock.c
> +++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c
> @@ -319,3 +319,67 @@ int cross_rcu_region(void *ctx)
> bpf_rcu_read_unlock();
> return 0;
> }
> +
> +__noinline
> +static int static_subprog(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + if (bpf_get_prandom_u32())
> + return ret + 42;
> + return ret + bpf_get_prandom_u32();
> +}
> +
> +__noinline
> +static int static_subprog_lock(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + bpf_rcu_read_lock();
> + if (bpf_get_prandom_u32())
> + return ret + 42;
> + return ret + bpf_get_prandom_u32();
> +}
> +
> +__noinline
> +static int static_subprog_unlock(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + bpf_rcu_read_unlock();
> + if (bpf_get_prandom_u32())
> + return ret + 42;
> + return ret + bpf_get_prandom_u32();
> +}
> +
> +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
> +int rcu_read_lock_subprog(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + bpf_rcu_read_lock();
> + if (bpf_get_prandom_u32())
> + ret += static_subprog(ctx);
> + bpf_rcu_read_unlock();
> + return 0;
> +}
> +
> +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
> +int rcu_read_lock_subprog_lock(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + ret += static_subprog_lock(ctx);
> + bpf_rcu_read_unlock();
> + return 0;
> +}
> +
> +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
> +int rcu_read_lock_subprog_unlock(void *ctx)
> +{
> + volatile int ret = 0;
> +
> + bpf_rcu_read_lock();
> + ret += static_subprog_unlock(ctx);
> + return 0;
> +}
> --
> 2.40.1
>
>
--
Regards
Yafang
