This is a note to let you know that I've just added the patch titled io_uring: add completion locking for iopoll to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: io_uring-add-completion-locking-for-iopoll.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 2ccc92f4effcfa1c51c4fcf1e34d769099d3cad4 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov <asml.silence@xxxxxxxxx> Date: Wed, 23 Nov 2022 11:33:36 +0000 Subject: io_uring: add completion locking for iopoll From: Pavel Begunkov <asml.silence@xxxxxxxxx> commit 2ccc92f4effcfa1c51c4fcf1e34d769099d3cad4 upstream. There are pieces of code that may allow iopoll to race filling cqes, temporarily add spinlocking around posting events. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Link: https://lore.kernel.org/r/84d86b5c117feda075471c5c9e65208e0dccf5d0.1669203009.git.asml.silence@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- io_uring/rw.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/io_uring/rw.c +++ b/io_uring/rw.c @@ -1063,6 +1063,7 @@ int io_do_iopoll(struct io_ring_ctx *ctx else if (!pos) return 0; + spin_lock(&ctx->completion_lock); prev = start; wq_list_for_each_resume(pos, prev) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); @@ -1077,11 +1078,11 @@ int io_do_iopoll(struct io_ring_ctx *ctx req->cqe.flags = io_put_kbuf(req, 0); __io_fill_cqe_req(req->ctx, req); } - + io_commit_cqring(ctx); + spin_unlock(&ctx->completion_lock); if (unlikely(!nr_events)) return 0; - io_commit_cqring(ctx); io_cqring_ev_posted_iopoll(ctx); pos = start ? start->next : ctx->iopoll_list.first; wq_list_cut(&ctx->iopoll_list, prev, start); Patches currently in stable-queue which might be from asml.silence@xxxxxxxxx are queue-6.0/io_uring-net-fix-cleanup-after-recycle.patch queue-6.0/io_uring-protect-cq_timeouts-with-timeout_lock.patch queue-6.0/io_uring-add-completion-locking-for-iopoll.patch queue-6.0/io_uring-improve-io_double_lock_ctx-fail-handling.patch