On Sun, May 24, 2020 at 02:56:35AM -0400, Keno Fischer wrote: > Just ran into this issue again, with what I think may be most compelling > example yet why this is problematic: > > The tracee incurred a signal, we PTRACE_SYSEMU'd to the rt_sigreturn, > which the tracer tried to emulate by applying the state from the signal frame. > However, the PTRACE_SYSEMU stop is a syscall-stop, so the tracer's write > to x7 was ignored and x7 retained the value it had in the signal handler, > which broke the tracee.
Yeah, that sounds like a good justification to add a way to stop this. Could you send a patch, please? Interestingly, I *thought* the current behaviour was needed by strace, but I can't find anything there that seems to require it. Oh well, we're stuck with it anyway. Will
