From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756381AbaEDQtM (ORCPT ); Sun, 4 May 2014 12:49:12 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35967 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753883AbaEDPla (ORCPT ); Sun, 4 May 2014 11:41:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Stefani Seibold Subject: [PATCH 3.14 064/158] USB: fix crash during hotplug of PCI USB controller card Date: Sun, 4 May 2014 11:39:33 -0400 Message-Id: <20140504154038.645614974@linuxfoundation.org> X-Mailer: git-send-email 1.9.0 In-Reply-To: <20140504154029.975081050@linuxfoundation.org> References: <20140504154029.975081050@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit a2ff864b53eac9a0e9b05bfe9d1781ccd6c2af71 upstream. The code in hcd-pci.c that matches up EHCI controllers with their companion UHCI or OHCI controllers assumes that the private drvdata fields don't get set too early. However, it turns out that this field gets set by usb_create_hcd(), before hcd-pci expects it, and this can result in a crash when two controllers are probed in parallel (as can happen when a new controller card is hotplugged). The companions_rwsem lock was supposed to prevent this sort of thing, but usb_create_hcd() is called outside the scope of the rwsem. A simple solution is to check that the root-hub pointer has been initialized as well as the drvdata field. This doesn't happen until usb_add_hcd() is called; that call and the check are both protected by the rwsem. This patch should be applied to stable kernels from 3.10 onward. Signed-off-by: Alan Stern Reported-by: Stefani Seibold Tested-by: Stefani Seibold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd-pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -75,7 +75,7 @@ static void for_each_companion(struct pc PCI_SLOT(companion->devfn) != slot) continue; companion_hcd = pci_get_drvdata(companion); - if (!companion_hcd) + if (!companion_hcd || !companion_hcd->self.root_hub) continue; fn(pdev, hcd, companion, companion_hcd); }