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=-13.1 required=3.0 tests=BAYES_00,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 CA761C4363A for ; Tue, 27 Oct 2020 00:21:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 966E420723 for ; Tue, 27 Oct 2020 00:21:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603758075; bh=H4nDnaO+Cug1tV+QNFmh+VgE58P76DwFWI5v8bfy9/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=L+DjKTX4VA9kOUjUpBGVCvD9PgS52OC0m6o1ZmGllbIkOtLCh5uaCV8lnSYuRkVwb mAfAxWatBnfg2R6/Cui+ZgS3wSdjoZL3EuDBVhH3aVB1nUL3IHFa8+sNJ3vE6Lbt41 /kFDXLC6qRIoLlY1mYTFYfxGaSJ9TtBNO4O+ozCA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733255AbgJ0AFw (ORCPT ); Mon, 26 Oct 2020 20:05:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:53734 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437872AbgJ0AEx (ORCPT ); Mon, 26 Oct 2020 20:04:53 -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 82F3F20754; Tue, 27 Oct 2020 00:04:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603757093; bh=H4nDnaO+Cug1tV+QNFmh+VgE58P76DwFWI5v8bfy9/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g933PPQbJQLFdrSCAu3erdfVo5GQXUn/hz6pm5QUZK4SE5IYKtLAKJgLAGYsxaP0i n1862FTAZ/qIkEwIn9mpNdm8hwI5yDweIrTsxczRJ4xGQNRzQFCtbFB7201wTKrK5i WBWiHApxUcABQAb0ZfpCN3Amh5ZGfoD/HFw+V/kE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Lang Dai , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.19 31/60] uio: free uio id after uio file node is freed Date: Mon, 26 Oct 2020 20:03:46 -0400 Message-Id: <20201027000415.1026364-31-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201027000415.1026364-1-sashal@kernel.org> References: <20201027000415.1026364-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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 9c788748bdc65..3926be6591471 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -1008,8 +1008,6 @@ 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); @@ -1021,6 +1019,8 @@ void uio_unregister_device(struct uio_info *info) device_unregister(&idev->dev); + uio_free_minor(idev); + return; } EXPORT_SYMBOL_GPL(uio_unregister_device); -- 2.25.1