From patchwork Mon May 14 08:21:20 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kai-Heng Feng X-Patchwork-Id: 912740 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=canonical.com Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 40ktvh2Hv6z9s0q; Mon, 14 May 2018 18:21:36 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1fI8jZ-00078Y-SM; Mon, 14 May 2018 08:21:29 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.86_2) (envelope-from ) id 1fI8jX-000787-TZ for kernel-team@lists.ubuntu.com; Mon, 14 May 2018 08:21:27 +0000 Received: from 2.general.khfeng.us.vpn ([10.172.68.175] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1fI8jX-0006Ce-3b for kernel-team@lists.ubuntu.com; Mon, 14 May 2018 08:21:27 +0000 From: Kai-Heng Feng To: kernel-team@lists.ubuntu.com Subject: [SRU] [B/C] [PATCH 1/1] xhci: Fix Kernel oops in xhci dbgtty Date: Mon, 14 May 2018 16:21:20 +0800 Message-Id: <20180514082120.10443-2-kai.heng.feng@canonical.com> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180514082120.10443-1-kai.heng.feng@canonical.com> References: <20180514082120.10443-1-kai.heng.feng@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Zhengjun Xing BugLink: https://bugs.launchpad.net/bugs/1768852 tty_unregister_driver may be called more than 1 time in some hotplug cases,it will cause the kernel oops. This patch checked dbc_tty_driver to make sure it is unregistered only 1 time. [ 175.741404] BUG: unable to handle kernel NULL pointer dereference at 0000000000000034 [ 175.742309] IP: tty_unregister_driver+0x9/0x70 [ 175.743148] PGD 0 P4D 0 [ 175.743981] Oops: 0000 [#1] SMP PTI [ 175.753904] RIP: 0010:tty_unregister_driver+0x9/0x70 [ 175.754817] RSP: 0018:ffffa8ff831d3bb0 EFLAGS: 00010246 [ 175.755753] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 175.756685] RDX: ffff92089c616000 RSI: ffffe64fe1b26080 RDI: 0000000000000000 [ 175.757608] RBP: ffff92086c988230 R08: 000000006c982701 R09: 00000001801e0016 [ 175.758533] R10: ffffa8ff831d3b48 R11: ffff92086c982100 R12: ffff92086c98827c [ 175.759462] R13: ffff92086c988398 R14: 0000000000000060 R15: ffff92089c5e9b40 [ 175.760401] FS: 0000000000000000(0000) GS:ffff9208a0100000(0000) knlGS:0000000000000000 [ 175.761334] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 175.762270] CR2: 0000000000000034 CR3: 000000011800a003 CR4: 00000000003606e0 [ 175.763225] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 175.764164] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 175.765091] Call Trace: [ 175.766014] xhci_dbc_tty_unregister_driver+0x11/0x30 [ 175.766960] xhci_dbc_exit+0x2a/0x40 [ 175.767889] xhci_stop+0x57/0x1c0 [ 175.768824] usb_remove_hcd+0x100/0x250 [ 175.769708] usb_hcd_pci_remove+0x68/0x130 [ 175.770574] pci_device_remove+0x3b/0xc0 [ 175.771435] device_release_driver_internal+0x157/0x230 [ 175.772343] pci_stop_bus_device+0x74/0xa0 [ 175.773205] pci_stop_bus_device+0x2b/0xa0 [ 175.774061] pci_stop_bus_device+0x2b/0xa0 [ 175.774907] pci_stop_bus_device+0x2b/0xa0 [ 175.775741] pci_stop_bus_device+0x2b/0xa0 [ 175.776618] pci_stop_bus_device+0x2b/0xa0 [ 175.777452] pci_stop_bus_device+0x2b/0xa0 [ 175.778273] pci_stop_bus_device+0x2b/0xa0 [ 175.779092] pci_stop_bus_device+0x2b/0xa0 [ 175.779908] pci_stop_bus_device+0x2b/0xa0 [ 175.780750] pci_stop_bus_device+0x2b/0xa0 [ 175.781543] pci_stop_and_remove_bus_device+0xe/0x20 [ 175.782338] pciehp_unconfigure_device+0xb8/0x160 [ 175.783128] pciehp_disable_slot+0x4f/0xd0 [ 175.783920] pciehp_power_thread+0x82/0xa0 [ 175.784766] process_one_work+0x147/0x3c0 [ 175.785564] worker_thread+0x4a/0x440 [ 175.786376] kthread+0xf8/0x130 [ 175.787174] ? rescuer_thread+0x360/0x360 [ 175.787964] ? kthread_associate_blkcg+0x90/0x90 [ 175.788798] ret_from_fork+0x35/0x40 Cc: # 4.16 Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Zhengjun Xing Tested-by: Christian Kellner Reviewed-by: Christian Kellner Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman (cherry picked from commit 7fc65d4c2ba9e5006c629669146c6876b65aa233) Signed-off-by: Kai-Heng Feng Acked-by: Andy Whitcroft --- drivers/usb/host/xhci-dbgtty.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c index 48811d72a94c..f64307fcaca0 100644 --- a/drivers/usb/host/xhci-dbgtty.c +++ b/drivers/usb/host/xhci-dbgtty.c @@ -318,9 +318,11 @@ int xhci_dbc_tty_register_driver(struct xhci_hcd *xhci) void xhci_dbc_tty_unregister_driver(void) { - tty_unregister_driver(dbc_tty_driver); - put_tty_driver(dbc_tty_driver); - dbc_tty_driver = NULL; + if (dbc_tty_driver) { + tty_unregister_driver(dbc_tty_driver); + put_tty_driver(dbc_tty_driver); + dbc_tty_driver = NULL; + } } static void dbc_rx_push(unsigned long _port)