From patchwork Tue Nov 3 20:35:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 316869 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, 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 65D47C388F7 for ; Tue, 3 Nov 2020 21:43:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FF4F22384 for ; Tue, 3 Nov 2020 21:43:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604439793; bh=7YV7fjb1BKsMrIzSZ6GJxSMv4pyVURgY527Izu1OOoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Mj3OM+XG6gNWJ3r1D77LnAusipAemkqtItbx8+GcNalY9wh0vZ8zXpaZEnxHST1Ms QnirOrjusvr5XDUJF4Va7kDBnvm2eUtKYFmWDjqAltxuN3625vs0FYVETMtU8ZZrQa pNVXaa54xJKuGyS3INiExgvgcRs1ArD5fd1c7S/c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732655AbgKCUy6 (ORCPT ); Tue, 3 Nov 2020 15:54:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:54726 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732651AbgKCUy5 (ORCPT ); Tue, 3 Nov 2020 15:54:57 -0500 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 8FD5F22226; Tue, 3 Nov 2020 20:54:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604436897; bh=7YV7fjb1BKsMrIzSZ6GJxSMv4pyVURgY527Izu1OOoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=anLJ71C2rnqTwaL03Q8x/TVRrof+31gTbbrVMT7PupwFS+UML+tsUg7kMyIMCKo6W NAtaEw2g/NxoXwMvnkTgKhQrluL2t188QTcf/4/hgAbqLn3JXrpR1DaoZCO8IbAgh4 8fU1I4mRNt4sQC9NYmq5/5fDXEvEqlYEWaNgrkp4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lang Dai , Sasha Levin Subject: [PATCH 5.4 058/214] uio: free uio id after uio file node is freed Date: Tue, 3 Nov 2020 21:35:06 +0100 Message-Id: <20201103203255.777547047@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201103203249.448706377@linuxfoundation.org> References: <20201103203249.448706377@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Lang Dai [ Upstream commit 8fd0e2a6df262539eaa28b0a2364cca10d1dc662 ] uio_register_device() do two things. 1) get an uio id from a global pool, e.g. the id is 2) create file nodes like /sys/class/uio/uio uio_unregister_device() do two things. 1) free the uio id and return it to the global pool 2) free the file node /sys/class/uio/uio There is a situation is that one worker is calling uio_unregister_device(), and another worker is calling uio_register_device(). If the two workers are X and Y, they go as below sequence, 1) X free the uio id 2) Y get an uio id 3) Y create file node /sys/class/uio/uio 4) X free the file note /sys/class/uio/uio Then it will failed at the 3rd step and cause the phenomenon we saw as it is creating a duplicated file node. Failure reports as follows: sysfs: cannot create duplicate filename '/class/uio/uio10' Call Trace: sysfs_do_create_link_sd.isra.2+0x9e/0xb0 sysfs_create_link+0x25/0x40 device_add+0x2c4/0x640 __uio_register_device+0x1c5/0x576 [uio] adf_uio_init_bundle_dev+0x231/0x280 [intel_qat] adf_uio_register+0x1c0/0x340 [intel_qat] adf_dev_start+0x202/0x370 [intel_qat] adf_dev_start_async+0x40/0xa0 [intel_qat] process_one_work+0x14d/0x410 worker_thread+0x4b/0x460 kthread+0x105/0x140 ? process_one_work+0x410/0x410 ? kthread_bind+0x40/0x40 ret_from_fork+0x1f/0x40 Code: 85 c0 48 89 c3 74 12 b9 00 10 00 00 48 89 c2 31 f6 4c 89 ef e8 ec c4 ff ff 4c 89 e2 48 89 de 48 c7 c7 e8 b4 ee b4 e8 6a d4 d7 ff <0f> 0b 48 89 df e8 20 fa f3 ff 5b 41 5c 41 5d 5d c3 66 0f 1f 84 ---[ end trace a7531c1ed5269e84 ]--- c6xxvf b002:00:00.0: Failed to register UIO devices c6xxvf b002:00:00.0: Failed to register UIO devices Signed-off-by: Lang Dai Link: https://lore.kernel.org/r/1600054002-17722-1-git-send-email-lang.dai@intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/uio/uio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index a57698985f9c4..8313f81968d51 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -1010,8 +1010,6 @@ void uio_unregister_device(struct uio_info *info) idev = info->uio_dev; - uio_free_minor(idev); - mutex_lock(&idev->info_lock); uio_dev_del_attributes(idev); @@ -1026,6 +1024,8 @@ void uio_unregister_device(struct uio_info *info) device_unregister(&idev->dev); + uio_free_minor(idev); + return; } EXPORT_SYMBOL_GPL(uio_unregister_device);