On 7/15/23 1:12 AM, Arnd Bergmann wrote: > On Fri, Jul 14, 2023, at 22:14, Jens Axboe wrote: >> On 7/14/23 12:33?PM, Arnd Bergmann wrote: >>> On Fri, Jul 14, 2023, at 17:47, Christian Brauner wrote: >>>> On Tue, Jul 11, 2023 at 04:18:13PM -0600, Jens Axboe wrote: >>>>>>> Does this require argument conversion for compat tasks? >>>>>>> >>>>>>> Even without the rusage argument, I think the siginfo >>>>>>> remains incompatible with 32-bit tasks, unfortunately. >>>>>> >>>>>> Hmm yes good point, if compat_siginfo and siginfo are different, then it >>>>>> does need handling for that. Would be a trivial addition, I'll make that >>>>>> change. Thanks Arnd! >>>>> >>>>> Should be fixed in the current version: >>>>> >>>>> https://git.kernel.dk/cgit/linux/commit/?h=io_uring-waitid&id=08f3dc9b7cedbd20c0f215f25c9a7814c6c601cc >>>> >>>> In kernel/signal.c in pidfd_send_signal() we have >>>> copy_siginfo_from_user_any() it seems that a similar version >>>> copy_siginfo_to_user_any() might be something to consider. We do have >>>> copy_siginfo_to_user32() and copy_siginfo_to_user(). But I may lack >>>> context why this wouldn't work here. >>> >>> We could add a copy_siginfo_to_user_any(), but I think open-coding >>> it is easier here, since the in_compat_syscall() check does not >>> work inside of the io_uring kernel thread, it has to be >>> "if (req->ctx->compat)" in order to match the wordsize of the task >>> that started the request. >> >> Yeah, unifying this stuff did cross my mind when adding another one. >> Which I think could still be done, you'd just need to pass in a 'compat' >> parameter similar to how it's done for iovec importing. >> >> But if it's ok with everybody I'd rather do that as a cleanup post this. > > Sure, keeping that separate seem best. > > Looking at what copy_siginfo_from_user_any() actually does, I don't > even think it's worth adapting copy_siginfo_to_user_any() for io_uring, > since it's already just a trivial wrapper, and adding another > argument would add more complexity overall than it saves. Yeah, took a look too this morning, and not sure there's much to reduce here that would make it cleaner. I'm going to send out a v2 with this unchanged, holler if people disagree. -- Jens Axboe
