From: Pavel Begunkov asml.silence@gmail.com
commit 31bff9a51b264df6d144931a6a5f1d6cc815ed4b upstream.
IOPOLL allows buffer remove/provide requests, but they doesn't synchronise by rules of IOPOLL, namely it have to hold uring_lock.
Cc: stable@vger.kernel.org # 5.7+ Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/io_uring.c | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-)
--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3944,11 +3944,17 @@ static int io_remove_buffers(struct io_k head = idr_find(&ctx->io_buffer_idr, p->bgid); if (head) ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs); - - io_ring_submit_lock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); - __io_req_complete(req, ret, 0, cs); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + __io_req_complete(req, ret, 0, cs); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + __io_req_complete(req, ret, 0, cs); + } return 0; }
@@ -4033,10 +4039,17 @@ static int io_provide_buffers(struct io_ } } out: - io_ring_submit_unlock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); - __io_req_complete(req, ret, 0, cs); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + __io_req_complete(req, ret, 0, cs); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + __io_req_complete(req, ret, 0, cs); + } return 0; }