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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 4B03EC388F9 for ; Sat, 31 Oct 2020 11:49:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15F812065D for ; Sat, 31 Oct 2020 11:49:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604144944; bh=IBDCAtZAeG0/LGaYSQXF5LKZWfH9gmejTmW2vzUoc1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jmn/cF/HYwFzx/Bud5RmCMV+/1UEi9z3ngmIoOaFfcQl50fPdT60CGIL+7IGX7hmJ mrllxIWoeLf3+v+0dzUmn/Uiq+1awLjK1KnY3TUzoGHyhzGC4qIq4p/byZSE7BctAL gAN0dz5TkY47U6aAVQAJUlYoXXcu9mDOscToig2E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727371AbgJaLtC (ORCPT ); Sat, 31 Oct 2020 07:49:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:43112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727983AbgJaLnN (ORCPT ); Sat, 31 Oct 2020 07:43:13 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2ED9F2074F; Sat, 31 Oct 2020 11:43:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604144592; bh=IBDCAtZAeG0/LGaYSQXF5LKZWfH9gmejTmW2vzUoc1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=udRR3kJ/zKG+EYQPieufB7DhPGOgkl76c3LaRfzceUgCh8GnYrnEjUdmZE1OVqnyg 7oAEGL0zW8Pcv3IcISNxDtAeVf87UzpnQJOEuooEkPe1tRY/PD4A6JEZIN9yAnDZof oFHjXrANysj9OeS7q8MZJNjY5azli5Yq7ik4omw0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Aloni , Leon Romanovsky , Jason Gunthorpe Subject: [PATCH 5.8 60/70] RDMA/addr: Fix race with netevent_callback()/rdma_addr_cancel() Date: Sat, 31 Oct 2020 12:36:32 +0100 Message-Id: <20201031113502.375472125@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201031113459.481803250@linuxfoundation.org> References: <20201031113459.481803250@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: Jason Gunthorpe commit 2ee9bf346fbfd1dad0933b9eb3a4c2c0979b633e upstream. This three thread race can result in the work being run once the callback becomes NULL: CPU1 CPU2 CPU3 netevent_callback() process_one_req() rdma_addr_cancel() [..] spin_lock_bh() set_timeout() spin_unlock_bh() spin_lock_bh() list_del_init(&req->list); spin_unlock_bh() req->callback = NULL spin_lock_bh() if (!list_empty(&req->list)) // Skipped! // cancel_delayed_work(&req->work); spin_unlock_bh() process_one_req() // again req->callback() // BOOM cancel_delayed_work_sync() The solution is to always cancel the work once it is completed so any in between set_timeout() does not result in it running again. Cc: stable@vger.kernel.org Fixes: 44e75052bc2a ("RDMA/rdma_cm: Make rdma_addr_cancel into a fence") Link: https://lore.kernel.org/r/20200930072007.1009692-1-leon@kernel.org Reported-by: Dan Aloni Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/core/addr.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -647,13 +647,12 @@ static void process_one_req(struct work_ req->callback = NULL; spin_lock_bh(&lock); + /* + * Although the work will normally have been canceled by the workqueue, + * it can still be requeued as long as it is on the req_list. + */ + cancel_delayed_work(&req->work); if (!list_empty(&req->list)) { - /* - * Although the work will normally have been canceled by the - * workqueue, it can still be requeued as long as it is on the - * req_list. - */ - cancel_delayed_work(&req->work); list_del_init(&req->list); kfree(req); }