On Tue, Jul 11, 2023 at 04:18:13PM -0600, Jens Axboe wrote: > On 7/11/23 3:22 PM, Jens Axboe wrote: > > On 7/11/23 3:11?PM, Arnd Bergmann wrote: > >> On Tue, Jul 11, 2023, at 22:43, Jens Axboe wrote: > >>> This adds support for an async version of waitid(2), in a fully async > >>> version. If an event isn't immediately available, wait for a callback > >>> to trigger a retry. > >>> > >>> The format of the sqe is as follows: > >>> > >>> sqe->len The 'which', the idtype being queried/waited for. > >>> sqe->fd The 'pid' (or id) being waited for. > >>> sqe->file_index The 'options' being set. > >>> sqe->addr2 A pointer to siginfo_t, if any, being filled in. > >>> > >>> buf_index, add3, and waitid_flags are reserved/unused for now. > >>> waitid_flags will be used for options for this request type. One > >>> interesting use case may be to add multi-shot support, so that the > >>> request stays armed and posts a notification every time a monitored > >>> process state change occurs. > >>> > >>> Note that this does not support rusage, on Arnd's recommendation. > >>> > >>> See the waitid(2) man page for details on the arguments. > >>> > >>> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > >> > >> 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.
