From: Pavel Begunkov asml.silence@gmail.com
commit c0713540f6d55c53dca65baaead55a5a8b20552d upstream.
If all completed requests in io_do_iopoll() were marked with REQ_F_CQE_SKIP, we'll not only skip CQE posting but also io_free_batch_list() leaking memory and resources.
Move @nr_events increment before REQ_F_CQE_SKIP check. We'll potentially return the value greater than the real one, but iopolling will deal with it and the userspace will re-iopoll if needed. In anyway, I don't think there are many use cases for REQ_F_CQE_SKIP + IOPOLL.
Fixes: 83a13a4181b0e ("io_uring: tweak iopoll CQE_SKIP event counting") Signed-off-by: Pavel Begunkov asml.silence@gmail.com Link: https://lore.kernel.org/r/5072fc8693fbfd595f89e5d4305bfcfd5d2f0a64.165018661... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/io_uring.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2612,11 +2612,10 @@ static int io_do_iopoll(struct io_ring_c /* order with io_complete_rw_iopoll(), e.g. ->result updates */ if (!smp_load_acquire(&req->iopoll_completed)) break; + nr_events++; if (unlikely(req->flags & REQ_F_CQE_SKIP)) continue; - __io_fill_cqe(ctx, req->user_data, req->result, io_put_kbuf(req)); - nr_events++; }
if (unlikely(!nr_events))