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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 3A7F5C3A5A9 for ; Mon, 4 May 2020 18:06:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 166E62087E for ; Mon, 4 May 2020 18:06:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615608; bh=w+yPL/bVXvDTiFWPzUWODEVmw/6jrMVQG1TYGt8QO3s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vqu80H5W1C8M29djmiGzTZTA88FeDFdLerhyr2+jh4wOh0zwYcp2groeXZP4qZigK q8DiOv/0LXNCsr48vhiyGO06sT0S4zRItN5IypfhW9rIGQcyDKgGU4xwzm7oBCG3w9 cg+ZGBz4ygYyvvMmtqx/AUKHjr7kcD4nXmJvSXNI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732022AbgEDSGr (ORCPT ); Mon, 4 May 2020 14:06:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:37250 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732010AbgEDSGo (ORCPT ); Mon, 4 May 2020 14:06:44 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 C20DB2087E; Mon, 4 May 2020 18:06:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615604; bh=w+yPL/bVXvDTiFWPzUWODEVmw/6jrMVQG1TYGt8QO3s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Sah/UtS8oGuKUF2WBmfxkf+XAVobMbiRMf3gNRU4fmcdBzY1373TJqQnJe5S1QFx6 I92d0MAnVZTi7IPgfGUxKrUj0JDTqkEJKnXjtHotfWw0buoPdOVoCX7HbmTY7Ksayc HXVzdiOffgez5EW8TupfH3M8+hJ5WoPqGHYZVlGE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Gunthorpe , Leon Romanovsky Subject: [PATCH 5.6 49/73] RDMA/core: Fix race between destroy and release FD object Date: Mon, 4 May 2020 19:57:52 +0200 Message-Id: <20200504165509.066749063@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200504165501.781878940@linuxfoundation.org> References: <20200504165501.781878940@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Leon Romanovsky commit f0abc761bbb9418876cc4d1ebc473e4ea6352e42 upstream. 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: Greg Kroah-Hartman --- drivers/infiniband/core/rdma_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -678,7 +678,6 @@ void rdma_lookup_put_uobject(struct ib_u 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 @@ -695,6 +694,7 @@ void rdma_lookup_put_uobject(struct ib_u break; } + uobj->uapi_object->type_class->lookup_put(uobj, mode); /* Pairs with the kref obtained by type->lookup_get */ uverbs_uobject_put(uobj); }