It is possible that we fail on xhci_mem_init, just before doing
the INIT_LIST_HEAD, and calling xhci_mem_cleanup.

Problem is that, the list_for_each_entry_safe macro, assumes
list heads are initialized (not NULL), and dereferences their 'next'
pointer, causing a kernel panic if this is not yet initialized.

Let's protect from that by moving inits to the beginning.

Signed-off-by: Sergio Aguirre <sergio.a.aguirre.rodrig...@intel.com>
---
 drivers/usb/host/xhci-mem.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 6dc238c..ffbdefc 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2255,6 +2255,9 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
        u32 page_size, temp;
        int i;
 
+       INIT_LIST_HEAD(&xhci->lpm_failed_devs);
+       INIT_LIST_HEAD(&xhci->cancel_cmd_list);
+
        page_size = xhci_readl(xhci, &xhci->op_regs->page_size);
        xhci_dbg(xhci, "Supported page size register = 0x%x\n", page_size);
        for (i = 0; i < 16; i++) {
@@ -2333,7 +2336,6 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
        xhci->cmd_ring = xhci_ring_alloc(xhci, 1, 1, TYPE_COMMAND, flags);
        if (!xhci->cmd_ring)
                goto fail;
-       INIT_LIST_HEAD(&xhci->cancel_cmd_list);
        xhci_dbg(xhci, "Allocated command ring at %p\n", xhci->cmd_ring);
        xhci_dbg(xhci, "First segment DMA is 0x%llx\n",
                        (unsigned long long)xhci->cmd_ring->first_seg->dma);
@@ -2444,8 +2446,6 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
        if (xhci_setup_port_arrays(xhci, flags))
                goto fail;
 
-       INIT_LIST_HEAD(&xhci->lpm_failed_devs);
-
        /* Enable USB 3.0 device notifications for function remote wake, which
         * is necessary for allowing USB 3.0 devices to do remote wakeup from
         * U3 (device suspend).
-- 
1.7.9.5

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