Commit c9a40292a4 upstream.
io_eventfd_do_signal() is invoked from an RCU callback, but when
dropping the reference to the io_ev_fd, it calls io_eventfd_free()
directly if the refcount drops to zero. This isn't correct, as any
potential freeing of the io_ev_fd should be deferred another RCU grace
period.
Just call io_eventfd_put() rather than open-code the dec-and-test and
free, which will correctly defer it another RCU grace period.
Fixes: 21a091b970 ("io_uring: signal registered eventfd to process deferred task work")
Reported-by: Jann Horn <jannh@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is pretty nicely abstracted already, but let's move it to a separate
file rather than have it in the main io_uring file. With that, we can
also move the io_ev_fd struct and enum out of global scope.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
