On 3/25/21 2:40 PM, Oleg Nesterov wrote: > On 03/25, Eric W. Biederman wrote: >> >> So looking quickly the flip side of the coin is gdb (and other >> debuggers) needs a way to know these threads are special, so it can know >> not to attach. > > may be, > >> I suspect getting -EPERM (or possibly a different error code) when >> attempting attach is the right was to know that a thread is not >> available to be debugged. > > may be. > > But I don't think we can blame gdb. The kernel changed the rules, and this > broke gdb. IOW, I don't agree this is gdb bug. Right, that's what I was getting at too - and it's likely not just gdb. We have to ensure that we don't break this use case, which seems to imply that we: 1) Just make it work, or 2) Make them hidden in such a way that gdb doesn't see them, but regular tooling does #2 seems fraught with peril, and maybe not even possible. -- Jens Axboe
