On Thu, Jan 5, 2023 at 1:00 AM Hao Sun <sunhao.th@xxxxxxxxx> wrote: > > > > Does syzbot running without any user space? > > Is syzbot itself a pid=1 ? and the only process ? > > If so, the error would makes sense. > > Yes, after read the C reproducer again, noticed that after a > bunch of sandbox setup, the pid of the reproducer process at > runtime is 1. > > > I guess we can add a safety check to bpf_send_signal_common > > to prevent syzbot from killing itself. > > Maybe something like this? This can avoid the panic, but won’t > allow task with pid=1 to send signal with prog. > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 23ce498bca97..94d2af2ce433 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -844,6 +844,8 @@ static int bpf_send_signal_common(u32 sig, enum pid_type type) > */ > if (unlikely(current->flags & (PF_KTHREAD | PF_EXITING))) > return -EPERM; > + if (unlikely(is_global_init(current))) > + return -EPERM; > if (unlikely(!nmi_uaccess_okay())) > return -EPERM; Yep. Good idea. Pls send an official patch.
