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authorAlan Stern <stern@rowland.harvard.edu>2014-04-14 13:48:47 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-16 13:59:12 -0700
commita2ff864b53eac9a0e9b05bfe9d1781ccd6c2af71 (patch)
treebdec07ff5673d3270b7c150e3d99cff1327a33d1 /drivers/usb/core
parent070c0b17f6a1ba39dff9be112218127e7e8fd456 (diff)
downloadlinux-stericsson-a2ff864b53eac9a0e9b05bfe9d1781ccd6c2af71.tar.gz
USB: fix crash during hotplug of PCI USB controller card
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 <stern@rowland.harvard.edu> Reported-by: Stefani Seibold <stefani@seibold.net> Tested-by: Stefani Seibold <stefani@seibold.net> CC: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/hcd-pci.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
index d59d99347d54..1f02e65fe305 100644
--- a/drivers/usb/core/hcd-pci.c
+++ b/drivers/usb/core/hcd-pci.c
@@ -75,7 +75,7 @@ static void for_each_companion(struct pci_dev *pdev, struct usb_hcd *hcd,
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);
}