Re: [PATCH bpf v2 2/2] bpf: add missing bpf_read_[un]lock_trace() for syscall program

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Sun, Aug 8, 2021 at 11:03 PM Yonghong Song <yhs@fb.com> wrote:
>
> Commit 79a7f8bdb159d ("bpf: Introduce bpf_sys_bpf() helper and program type.")
> added support for syscall program, which is a sleepable program.
> But the program run missed bpf_read_lock_trace()/bpf_read_unlock_trace(),
> which is needed to ensure proper rcu callback invocations.
> This patch added bpf_read_[un]lock_trace() properly.
>
> Fixes: 79a7f8bdb159d ("bpf: Introduce bpf_sys_bpf() helper and program type.")
> Signed-off-by: Yonghong Song <yhs@fb.com>
> ---

LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

>  net/bpf/test_run.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index 1cc75c811e24..caa16bf30fb5 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -7,6 +7,7 @@
>  #include <linux/vmalloc.h>
>  #include <linux/etherdevice.h>
>  #include <linux/filter.h>
> +#include <linux/rcupdate_trace.h>
>  #include <linux/sched/signal.h>
>  #include <net/bpf_sk_storage.h>
>  #include <net/sock.h>
> @@ -951,7 +952,10 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
>                         goto out;
>                 }
>         }
> +
> +       rcu_read_lock_trace();
>         retval = bpf_prog_run_pin_on_cpu(prog, ctx);
> +       rcu_read_unlock_trace();
>
>         if (copy_to_user(&uattr->test.retval, &retval, sizeof(u32))) {
>                 err = -EFAULT;
> --
> 2.30.2
>