From c462ac871f49753eca86bb960f573b993976a5ea Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Mon, 16 Jan 2023 16:22:12 +0200 Subject: [PATCH] xhci: Fix null pointer dereference when host dies commit a2bc47c43e70cf904b1af49f76d572326c08bca7 upstream. Make sure xhci_free_dev() and xhci_kill_endpoint_urbs() do not race and cause null pointer dereference when host suddenly dies. Usb core may call xhci_free_dev() which frees the xhci->devs[slot_id] virt device at the same time that xhci_kill_endpoint_urbs() tries to loop through all the device's endpoints, checking if there are any cancelled urbs left to give back. hold the xhci spinlock while freeing the virt device Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20230116142216.1141605-4-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 3636fa4..1b01d25 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3962,6 +3962,7 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev) struct xhci_hcd *xhci = hcd_to_xhci(hcd); struct xhci_virt_device *virt_dev; struct xhci_slot_ctx *slot_ctx; + unsigned long flags; int i, ret; /* @@ -3990,7 +3991,11 @@ static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev) } virt_dev->udev = NULL; xhci_disable_slot(xhci, udev->slot_id); + + spin_lock_irqsave(&xhci->lock, flags); xhci_free_virt_device(xhci, udev->slot_id); + spin_unlock_irqrestore(&xhci->lock, flags); + } int xhci_disable_slot(struct xhci_hcd *xhci, u32 slot_id) -- 2.7.4