This is a note to let you know that I've just added the patch titled
USB: fix crash during hotplug of PCI USB controller card
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From a2ff864b53eac9a0e9b05bfe9d1781ccd6c2af71 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 14 Apr 2014 13:48:47 -0400
Subject: 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@xxxxxxxxxxxxxxxxxxx>
Reported-by: Stefani Seibold <stefani@xxxxxxxxxxx>
Tested-by: Stefani Seibold <stefani@xxxxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/hcd-pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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);
}
--
1.9.0
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