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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 CFEB6C38A24 for ; Thu, 7 May 2020 14:33:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A763D2073A for ; Thu, 7 May 2020 14:33:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588862015; bh=XbnFtCXYMLOqIB6JPSZmw6i8y0K9dGA+/5iIuo36EkU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=J79Dfu7hsqdPWM2dIm1sfylJENnNhn2hYBWFkKxwra1vuawqANRnFa3vZGhlL+o9H k50xTrkYAeGYUnmfVqEZDsYQonlYmK6St9iznpfQFD4IzVaBGiY+eYxu0TMd/23dd9 ktspPzArNnCzL6ngWq8b4NdXkjjXkdv/LZx3brgw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728306AbgEGOd2 (ORCPT ); Thu, 7 May 2020 10:33:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:57390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728582AbgEGO3d (ORCPT ); Thu, 7 May 2020 10:29:33 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8B4A120838; Thu, 7 May 2020 14:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588861773; bh=XbnFtCXYMLOqIB6JPSZmw6i8y0K9dGA+/5iIuo36EkU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zFewgdpSbk7WqBX4Em4rtNuCIC/RT/jZM/r0ew88Ae6IOhb/0dyoU+5qmmKTAtaTN Z4ReIhLkc0Mf6KhzBjp7x7DXaGPITf4hkJw5ti/sCn36NQcF9qAKbCg5De0eWm1YzF M75mL1F0EzslnovN0p1LyWDzKB/R171TDzRqytfU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Leon Romanovsky , Jason Gunthorpe , Sasha Levin , linux-rdma@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 13/20] RDMA/core: Fix race between destroy and release FD object Date: Thu, 7 May 2020 10:29:09 -0400 Message-Id: <20200507142917.26612-13-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200507142917.26612-1-sashal@kernel.org> References: <20200507142917.26612-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Leon Romanovsky [ Upstream commit f0abc761bbb9418876cc4d1ebc473e4ea6352e42 ] The call to ->lookup_put() was too early and it caused an unlock of the read/write protection of the uobject after the FD was put. This allows a race: CPU1 CPU2 rdma_lookup_put_uobject() lookup_put_fd_uobject() fput() fput() uverbs_uobject_fd_release() WARN_ON(uverbs_try_lock_object(uobj, UVERBS_LOOKUP_WRITE)); atomic_dec(usecnt) Fix the code by changing the order, first unlock and call to ->lookup_put() after that. Fixes: 3832125624b7 ("IB/core: Add support for idr types") Link: https://lore.kernel.org/r/20200423060122.6182-1-leon@kernel.org Suggested-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky Signed-off-by: Jason Gunthorpe Signed-off-by: Sasha Levin --- drivers/infiniband/core/rdma_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c index 52737ad88bf1a..bf937fec50dca 100644 --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -697,7 +697,6 @@ void rdma_lookup_put_uobject(struct ib_uobject *uobj, enum rdma_lookup_mode mode) { assert_uverbs_usecnt(uobj, mode); - uobj->uapi_object->type_class->lookup_put(uobj, mode); /* * In order to unlock an object, either decrease its usecnt for * read access or zero it in case of exclusive access. See @@ -714,6 +713,7 @@ void rdma_lookup_put_uobject(struct ib_uobject *uobj, break; } + uobj->uapi_object->type_class->lookup_put(uobj, mode); /* Pairs with the kref obtained by type->lookup_get */ uverbs_uobject_put(uobj); } -- 2.20.1