From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD7FBC4160E for ; Tue, 2 Mar 2021 05:08:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BB7C061606 for ; Tue, 2 Mar 2021 05:08:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1444148AbhCBCju (ORCPT ); Mon, 1 Mar 2021 21:39:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:59346 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236826AbhCATyS (ORCPT ); Mon, 1 Mar 2021 14:54:18 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7843365365; Mon, 1 Mar 2021 17:54:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614621272; bh=RpWlMqKLpjC0+hoFIfV83hBF/JaoP8PGOoi1vm9co04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nIiBb8OpmeMaolaGxlNdyc64Pou+xZS2W+kYytwKFBENHYktVI8wkKcEJSBUcnJ0B TMmshe+xn8+Xm+iwUTloOKnE0tkT9xjoBXnzimSRz84hIoHeEY1MGMCf5NkCPi8SDd TFi237n0kdLeJLOm78t5XxnpBtNYZGWKm8/pbOuo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Gunthorpe , Chuck Lever , Sasha Levin Subject: [PATCH 5.11 455/775] svcrdma: Hold private mutex while invoking rdma_accept() Date: Mon, 1 Mar 2021 17:10:23 +0100 Message-Id: <20210301161224.039557981@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161201.679371205@linuxfoundation.org> References: <20210301161201.679371205@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chuck Lever [ Upstream commit 0ac24c320c4d89a9de6ec802591398b8675c7b3c ] RDMA core mutex locking was restructured by commit d114c6feedfe ("RDMA/cma: Add missing locking to rdma_accept()") [Aug 2020]. When lock debugging is enabled, the RPC/RDMA server trips over the new lockdep assertion in rdma_accept() because it doesn't call rdma_accept() from its CM event handler. As a temporary fix, have svc_rdma_accept() take the handler_mutex explicitly. In the meantime, let's consider how to restructure the RPC/RDMA transport to invoke rdma_accept() from the proper context. Calls to svc_rdma_accept() are serialized with calls to svc_rdma_free() by the generic RPC server layer. Suggested-by: Jason Gunthorpe Link: https://lore.kernel.org/linux-rdma/20210209154014.GO4247@nvidia.com/ Fixes: d114c6feedfe ("RDMA/cma: Add missing locking to rdma_accept()") Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- net/sunrpc/xprtrdma/svc_rdma_transport.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c index afba4e9d5425d..c895f80df659c 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_transport.c +++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c @@ -475,9 +475,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) if (!svc_rdma_post_recvs(newxprt)) goto errout; - /* Swap out the handler */ - newxprt->sc_cm_id->event_handler = svc_rdma_cma_handler; - /* Construct RDMA-CM private message */ pmsg.cp_magic = rpcrdma_cmp_magic; pmsg.cp_version = RPCRDMA_CMP_VERSION; @@ -498,7 +495,10 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt) } conn_param.private_data = &pmsg; conn_param.private_data_len = sizeof(pmsg); + rdma_lock_handler(newxprt->sc_cm_id); + newxprt->sc_cm_id->event_handler = svc_rdma_cma_handler; ret = rdma_accept(newxprt->sc_cm_id, &conn_param); + rdma_unlock_handler(newxprt->sc_cm_id); if (ret) { trace_svcrdma_accept_err(newxprt, ret); goto errout; -- 2.27.0