@@ -1228,6 +1228,17 @@ static void xhci_cmd_to_noop(struct xhci_hcd *xhci, struct xhci_cd *cur_cd)
cur_seg = find_trb_seg(xhci->cmd_ring->first_seg,
xhci->cmd_ring->dequeue, &cycle_state);
+ if (!cur_seg) {
+ xhci_warn(xhci, "Command ring mismatch, dequeue = %p %llx (dma)\n",
+ xhci->cmd_ring->dequeue,
+ (unsigned long long)
+ xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
+ xhci->cmd_ring->dequeue));
+ xhci_debug_ring(xhci, xhci->cmd_ring);
+ xhci_dbg_ring_ptrs(xhci, xhci->cmd_ring);
+ return;
+ }
+
/* find the command trb matched by cd from command ring */
for (cmd_trb = xhci->cmd_ring->dequeue;
cmd_trb != xhci->cmd_ring->enqueue;
This is a note to let you know that I have just added a patch titled xhci: Fix potential NULL ptr deref in command cancellation. to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.yuz tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From 025cc33e2f19b4430ca17fdb555031574a2d500d Mon Sep 17 00:00:00 2001 From: Sarah Sharp <sarah.a.sharp@linux.intel.com> Date: Tue, 16 Oct 2012 13:17:43 -0700 Subject: [PATCH] xhci: Fix potential NULL ptr deref in command cancellation. commit 43a09f7fb01fa1e091416a2aa49b6c666458c1ee upstream. The command cancellation code doesn't check whether find_trb_seg() couldn't find the segment that contains the TRB to be canceled. This could cause a NULL pointer deference later in the function when next_trb is called. It's unlikely to happen unless something is wrong with the command ring pointers, so add some debugging in case it happens. This patch should be backported to stable kernels as old as 3.0, that contain the commit b63f4053cc8aa22a98e3f9a97845afe6c15d0a0d "xHCI: handle command after aborting the command ring". Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- drivers/usb/host/xhci-ring.c | 11 +++++++++++ 1 file changed, 11 insertions(+) -- 1.7.9.5