From patchwork Wed Jul 22 11:57:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Weitao Wang X-Patchwork-Id: 11678377 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F41C7912 for ; Wed, 22 Jul 2020 12:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E0B5720787 for ; Wed, 22 Jul 2020 12:13:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728171AbgGVMNC convert rfc822-to-8bit (ORCPT ); Wed, 22 Jul 2020 08:13:02 -0400 Received: from ZXSHCAS2.zhaoxin.com ([203.148.12.82]:46651 "EHLO ZXSHCAS2.zhaoxin.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726161AbgGVMNC (ORCPT ); Wed, 22 Jul 2020 08:13:02 -0400 X-Greylist: delayed 902 seconds by postgrey-1.27 at vger.kernel.org; Wed, 22 Jul 2020 08:13:00 EDT Received: from zxbjmbx1.zhaoxin.com (10.29.252.163) by ZXSHCAS2.zhaoxin.com (10.28.252.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Wed, 22 Jul 2020 19:57:53 +0800 Received: from localhost.localdomain (114.242.248.179) by zxbjmbx1.zhaoxin.com (10.29.252.163) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Wed, 22 Jul 2020 19:57:51 +0800 From: WeitaoWangoc To: , , , , , , , , CC: , , , , Subject: [PATCH] USB:Fix kernel NULL pointer when unbind UHCI form vfio-pci Date: Wed, 22 Jul 2020 19:57:48 +0800 Message-ID: <1595419068-4812-1-git-send-email-WeitaoWang-oc@zhaoxin.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 X-Originating-IP: [114.242.248.179] X-ClientProxiedBy: ZXSHCAS1.zhaoxin.com (10.28.252.161) To zxbjmbx1.zhaoxin.com (10.29.252.163) Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This bug is found in Zhaoxin platform, but it's a commom code bug. Fail sequence: step1: Unbind UHCI controller from native driver; step2: Bind UHCI controller to vfio-pci, which will put UHCI controller in one vfio group's device list and set UHCI's dev->driver_data to struct vfio-pci(for UHCI) step3: Unbind EHCI controller from native driver, will try to tell UHCI native driver that "I'm removed by set companion_hcd->self.hs_companion to NULL. However, companion_hcd get from UHCI's dev->driver_data that has modified by vfio-pci already.So, the vfio-pci structure will be damaged! step4: Bind EHCI controller to vfio-pci driver, which will put EHCI controller in the same vfio group as UHCI controller; ... ... step5: Unbind UHCI controller from vfio-pci, which will delete UHCI from vfio group' device list that has been damaged in step 3. So,delete operation can random result into a NULL pointer dereference with the below stack dump. step6: Bind UHCI controller to native driver; step7: Unbind EHCI controller from vfio-pci, which will try to remove EHCI controller from the vfio group; step8: Bind EHCI controller to native driver; [ 929.114641] uhci_hcd 0000:00:10.0: remove, state 1 [ 929.114652] usb usb1: USB disconnect, device number 1 [ 929.114655] usb 1-1: USB disconnect, device number 2 [ 929.270313] usb 1-2: USB disconnect, device number 3 [ 929.318404] uhci_hcd 0000:00:10.0: USB bus 1 deregistered [ 929.343029] uhci_hcd 0000:00:10.1: remove, state 4 [ 929.343045] usb usb3: USB disconnect, device number 1 [ 929.343685] uhci_hcd 0000:00:10.1: USB bus 3 deregistered [ 929.369087] ehci-pci 0000:00:10.7: remove, state 4 [ 929.369102] usb usb4: USB disconnect, device number 1 [ 929.370325] ehci-pci 0000:00:10.7: USB bus 4 deregistered [ 932.398494] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 [ 932.398496] PGD 42a67d067 P4D 42a67d067 PUD 42a65f067 PMD 0 [ 932.398502] Oops: 0002 [#2] SMP NOPTI [ 932.398505] CPU: 2 PID: 7824 Comm: vfio_unbind.sh Tainted: P D 4.19.65-2020051917-rainos #1 [ 932.398506] Hardware name: Shanghai Zhaoxin Semiconductor Co., Ltd. HX002EH/HX002EH, BIOS HX002EH0_01_R480_R_200408 04/08/2020 [ 932.398513] RIP: 0010:vfio_device_put+0x31/0xa0 [vfio] [ 932.398515] Code: 89 e5 41 54 53 4c 8b 67 18 48 89 fb 49 8d 74 24 30 e8 e3 0e f3 de 84 c0 74 67 48 8b 53 20 48 8b 43 28 48 8b 7b 18 48 89 42 08 <48> 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 43 20 48 b8 00 02 00 [ 932.398516] RSP: 0018:ffffbbfd04cffc18 EFLAGS: 00010202 [ 932.398518] RAX: 0000000000000000 RBX: ffff92c7ea717880 RCX: 0000000000000000 [ 932.398519] RDX: ffff92c7ea713620 RSI: ffff92c7ea713630 RDI: ffff92c7ea713600 [ 932.398521] RBP: ffffbbfd04cffc28 R08: ffff92c7f02a8080 R09: ffff92c7efc03980 [ 932.398522] R10: ffffbbfd04cff9a8 R11: 0000000000000000 R12: ffff92c7ea713600 [ 932.398523] R13: ffff92c7ed8bb0a8 R14: ffff92c7ea717880 R15: 0000000000000000 [ 932.398525] FS: 00007f3031500740(0000) GS:ffff92c7f0280000(0000) knlGS:0000000000000000 [ 932.398526] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 932.398527] CR2: 0000000000000000 CR3: 0000000428626004 CR4: 0000000000160ee0 [ 932.398528] Call Trace: [ 932.398534] vfio_del_group_dev+0xe8/0x2a0 [vfio] [ 932.398539] ? __blocking_notifier_call_chain+0x52/0x60 [ 932.398542] ? do_wait_intr_irq+0x90/0x90 [ 932.398546] ? iommu_bus_notifier+0x75/0x100 [ 932.398551] vfio_pci_remove+0x20/0xa0 [vfio_pci] [ 932.398554] pci_device_remove+0x3e/0xc0 [ 932.398557] device_release_driver_internal+0x17a/0x240 [ 932.398560] device_release_driver+0x12/0x20 [ 932.398561] unbind_store+0xee/0x180 [ 932.398564] drv_attr_store+0x27/0x40 [ 932.398567] sysfs_kf_write+0x3c/0x50 [ 932.398568] kernfs_fop_write+0x125/0x1a0 [ 932.398572] __vfs_write+0x3a/0x190 [ 932.398575] ? apparmor_file_permission+0x1a/0x20 [ 932.398577] ? security_file_permission+0x3b/0xc0 [ 932.398581] ? _cond_resched+0x1a/0x50 [ 932.398582] vfs_write+0xb8/0x1b0 [ 932.398584] ksys_write+0x5c/0xe0 [ 932.398586] __x64_sys_write+0x1a/0x20 [ 932.398589] do_syscall_64+0x5a/0x110 [ 932.398592] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Using virt-manager/qemu to boot guest os, we can see the same fail sequence! Fix this by check for UHCI driver loaded or not before modifiy UHCI's dev->driver_data, which will happen in ehci native driver probe/remove. Signed-off-by: WeitaoWangoc --- drivers/usb/core/hcd-pci.c | 5 +++++ 1 file changed, 5 insertions(+) -- 2.7.4 保密声明： 本邮件含有保密或专有信息，仅供指定收件人使用。严禁对本邮件或其内容做任何未经授权的查阅、使用、复制或转发。 CONFIDENTIAL NOTE: This email contains confidential or legally privileged information and is for the sole use of its intended recipient. Any unauthorized review, use, copying or forwarding of this email or the content of this email is strictly prohibited. diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index 1547aa6..484f2a0 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -34,6 +34,7 @@ static DECLARE_RWSEM(companions_rwsem); #define CL_OHCI PCI_CLASS_SERIAL_USB_OHCI #define CL_EHCI PCI_CLASS_SERIAL_USB_EHCI +#define PCI_DEV_DRV_FLAG 2 static inline int is_ohci_or_uhci(struct pci_dev *pdev) { return pdev->class == CL_OHCI || pdev->class == CL_UHCI; @@ -68,6 +69,8 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd, if (companion->class != CL_UHCI && companion->class != CL_OHCI && companion->class != CL_EHCI) continue; + if (!(companion->priv_flags & PCI_DEV_DRV_FLAG)) + continue; companion_hcd = pci_get_drvdata(companion); if (!companion_hcd || !companion_hcd->self.root_hub) @@ -254,6 +257,7 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id, } pci_set_master(dev); + dev->priv_flags | = PCI_DEV_DRV_FLAG; /* Note: dev_set_drvdata must be called while holding the rwsem */ if (dev->class == CL_EHCI) { @@ -326,6 +330,7 @@ void usb_hcd_pci_remove(struct pci_dev *dev) local_irq_disable(); usb_hcd_irq(0, hcd); local_irq_enable(); + dev->priv_flags & = ~PCI_DEV_DRV_FLAG; /* Note: dev_set_drvdata must be called while holding the rwsem */ if (dev->class == CL_EHCI) {