From 27243048b7cde746d3910f95e99b607d7f549bda Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sun, 6 Dec 2020 22:22:43 +0000 Subject: [PATCH 2504/2944] io_uring: fix racy IOPOLL completions fix #32041927 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: # 5.7+ Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Jeffle Xu Reviewed-by: Joseph Qi --- fs/io_uring.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index ecad074..bfe870f 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3554,10 +3554,18 @@ static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock) 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); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + io_req_complete(req, ret); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + io_req_complete(req, ret); + } + return 0; } @@ -3642,10 +3650,18 @@ static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock) } } out: - io_ring_submit_unlock(ctx, !force_nonblock); if (ret < 0) req_set_fail_links(req); - io_req_complete(req, ret); + + /* need to hold the lock to complete IOPOLL requests */ + if (ctx->flags & IORING_SETUP_IOPOLL) { + io_req_complete(req, ret); + io_ring_submit_unlock(ctx, !force_nonblock); + } else { + io_ring_submit_unlock(ctx, !force_nonblock); + io_req_complete(req, ret); + } + return 0; } -- 1.8.3.1