From patchwork Wed Oct 16 10:19:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 176448 Delivered-To: patch@linaro.org Received: by 2002:ac9:3c86:0:0:0:0:0 with SMTP id w6csp6967064ocf; Wed, 16 Oct 2019 03:23:05 -0700 (PDT) X-Google-Smtp-Source: APXvYqyhI247ZjeEcIcWLp9r2WAjtoQr87OV09g3Bqq1R1Iy0JqyJPHBnL6hLaldz/mvbmPGweWd X-Received: by 2002:aa7:cf8c:: with SMTP id z12mr11016949edx.28.1571221385812; Wed, 16 Oct 2019 03:23:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1571221385; cv=none; d=google.com; s=arc-20160816; b=e/TzTKTVZKr8gQraSkTW59VYPNKjDV0Xz4OtfdPFFV2d/5qJ5zmZ/vZGOttgSC+x1I v6CKVKOrvecqJoZplVMyBdTF75BmIsAzV0yvs0UypFqYwuwjytR+XlEEu5k5xRPaxpZD RHc+shE2kt+M8Qs2ZErPf6Q3pGz/qmOJpn4iBzOX7aSbfAiRvSXW4vUKO6DgmGEzb2g/ cjzmEP+PlBmWPLh2nbzHYtWgaGsSICxG+PNFHXvSO/ZNX0V9BGEvCmFLM2OPF9wICTew lEap70Gt8q/VpSQ7wvVAvg1qOunnKPwIWUBeH2tjR2NTsVayy/++pThECHsPoA11S6GS uTTA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:mime-version:message-id:date:subject:cc :to:from; bh=eJyM+pNijbtyLYKlKN7tCpikJvN5Zb3QRFkyCgW5dpE=; b=MzABjR7QxH+IjZjyOzbvx6p27uY43EJs5JekuOXg3yHrWMsAGpEGTP1lIWghSAccL5 Kv5HG3Wzsrj/FEoMC0D9bK2nNFwg+OO5axf0G6ms8RjEYFO55qAA1h8Gq6i0Xf/rY3ka y9SvDu9T9/UFo+vqy453uw6PrY8dJarb5SrEn4jjF8o3fD4grK1XcnGnD0thwxze+Tfd P6mkSu5qrt0eLMzXCp7w/axkQ47VBg4xfebjOS/o+Tc9QA4aZb3mbU2sLOZbWozA8v7M H/y+qyzbAsvqHXZFjvjE6Ng8lBVNLv0DuloEU2onJDn6wLrjM/uAAXeXNXJTTWZPOyQ3 uDvw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id z33si16533054edz.314.2019.10.16.03.23.05; Wed, 16 Oct 2019 03:23:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392363AbfJPKXC (ORCPT + 26 others); Wed, 16 Oct 2019 06:23:02 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:47100 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726394AbfJPKXC (ORCPT ); Wed, 16 Oct 2019 06:23:02 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 7BE6C3E9025F397CF751; Wed, 16 Oct 2019 18:22:59 +0800 (CST) Received: from localhost.localdomain (10.67.212.75) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Wed, 16 Oct 2019 18:22:53 +0800 From: John Garry To: CC: , , , John Garry Subject: [PATCH] libata: Ensure ata_port probe has completed before detach Date: Wed, 16 Oct 2019 18:19:52 +0800 Message-ID: <1571221192-216909-1-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Originating-IP: [10.67.212.75] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With CONFIG_DEBUG_TEST_DRIVER_REMOVE set, we may find the following WARN: [ 23.452574] ------------[ cut here ]------------ [ 23.457190] WARNING: CPU: 59 PID: 1 at drivers/ata/libata-core.c:6676 ata_host_detach+0x15c/0x168 [ 23.466047] Modules linked in: [ 23.469092] CPU: 59 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc1-00010-g5b83fd27752b-dirty #296 [ 23.477776] Hardware name: Huawei D06 /D06, BIOS Hisilicon D06 UEFI RC0 - V1.16.01 03/15/2019 [ 23.486286] pstate: a0c00009 (NzCv daif +PAN +UAO) [ 23.491065] pc : ata_host_detach+0x15c/0x168 [ 23.495322] lr : ata_host_detach+0x88/0x168 [ 23.499491] sp : ffff800011cabb50 [ 23.502792] x29: ffff800011cabb50 x28: 0000000000000007 [ 23.508091] x27: ffff80001137f068 x26: ffff8000112c0c28 [ 23.513390] x25: 0000000000003848 x24: ffff0023ea185300 [ 23.518689] x23: 0000000000000001 x22: 00000000000014c0 [ 23.523987] x21: 0000000000013740 x20: ffff0023bdc20000 [ 23.529286] x19: 0000000000000000 x18: 0000000000000004 [ 23.534584] x17: 0000000000000001 x16: 00000000000000f0 [ 23.539883] x15: ffff0023eac13790 x14: ffff0023eb76c408 [ 23.545181] x13: 0000000000000000 x12: ffff0023eac13790 [ 23.550480] x11: ffff0023eb76c228 x10: 0000000000000000 [ 23.555779] x9 : ffff0023eac13798 x8 : 0000000040000000 [ 23.561077] x7 : 0000000000000002 x6 : 0000000000000001 [ 23.566376] x5 : 0000000000000002 x4 : 0000000000000000 [ 23.571674] x3 : ffff0023bf08a0bc x2 : 0000000000000000 [ 23.576972] x1 : 3099674201f72700 x0 : 0000000000400284 [ 23.582272] Call trace: [ 23.584706] ata_host_detach+0x15c/0x168 [ 23.588616] ata_pci_remove_one+0x10/0x18 [ 23.592615] ahci_remove_one+0x20/0x40 [ 23.596356] pci_device_remove+0x3c/0xe0 [ 23.600267] really_probe+0xdc/0x3e0 [ 23.603830] driver_probe_device+0x58/0x100 [ 23.608000] device_driver_attach+0x6c/0x90 [ 23.612169] __driver_attach+0x84/0xc8 [ 23.615908] bus_for_each_dev+0x74/0xc8 [ 23.619730] driver_attach+0x20/0x28 [ 23.623292] bus_add_driver+0x148/0x1f0 [ 23.627115] driver_register+0x60/0x110 [ 23.630938] __pci_register_driver+0x40/0x48 [ 23.635199] ahci_pci_driver_init+0x20/0x28 [ 23.639372] do_one_initcall+0x5c/0x1b0 [ 23.643199] kernel_init_freeable+0x1a4/0x24c [ 23.647546] kernel_init+0x10/0x108 [ 23.651023] ret_from_fork+0x10/0x18 [ 23.654590] ---[ end trace 634a14b675b71c13 ]--- With KASAN also enabled, we may also get many use-after-free reports. The issue is that when CONFIG_DEBUG_TEST_DRIVER_REMOVE is set, we may attempt to detach the ata_port before it has been probed. This is because the ata_ports are async probed, meaning that there is no guarantee that the ata_port has probed prior to detach. When the ata_port does probe in this scenario, we get all sorts of issues as the detach may have already happened. Fix by ensuring synchronisation with async_synchronize_full(). We could alternatively use the cookie returned from the ata_port probe async_schedule() call, but that means managing the cookie, so more complicated. Signed-off-by: John Garry --- Note: This has only been boot tested and manual driver remove/add. My system has no disk attached to the ahci host. -- 2.17.1 diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c index 28c492be0a57..74c9b3032d46 100644 --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -6708,6 +6708,9 @@ void ata_host_detach(struct ata_host *host) { int i; + /* Ensure ata_port probe has completed */ + async_synchronize_full(); + for (i = 0; i < host->n_ports; i++) ata_port_detach(host->ports[i]);