Re: [PATCH 1/3] ptrace,syscall_user_dispatch: Implement Syscall User Dispatch Suspension

On Mon, Jan 09, 2023 at 10:33:46AM -0500, Gregory Price wrote:

@@ -36,6 +37,10 @@ bool syscall_user_dispatch(struct pt_regs *regs) struct syscall_user_dispatch *sd = &current->syscall_dispatch; char state;

• if (IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) &&

• 	unlikely(current->ptrace & PT_SUSPEND_SYSCALL_USER_DISPATCH))
  

• return false;
  

• if (likely(instruction_pointer(regs) - sd->offset < sd->len)) return false;

So by making syscall_user_dispatch() return false, we'll make syscall_trace_enter() continue to handle things, and supposedly you want to land in ptrace_report_syscall_entry(), right?

diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 54482193e1ed..a6ad815bd4be 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -370,6 +370,11 @@ static int check_ptrace_options(unsigned long data) if (data & ~(unsigned long)PTRACE_O_MASK) return -EINVAL;

• if (unlikely(data & PTRACE_O_SUSPEND_SYSCALL_USER_DISPATCH)) {

• if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTART))
  

• 	return -EINVAL;
  

• }

Should setting this then not also depend on having SYSCALL_WORK_SYSCALL_TRACE set? Because without that, you get 'funny' things.