This is a note to let you know that I've just added the patch titled xhci: don't create endpoint debugfs entry before ring buffer is set. to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xhci-don-t-create-endpoint-debugfs-entry-before-ring.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f9cb041f886a0125a36a3b3469feab83c66d6ab8 Author: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Date: Fri Sep 18 16:17:51 2020 +0300 xhci: don't create endpoint debugfs entry before ring buffer is set. [ Upstream commit 167657a1bb5fcde53ac304ce6c564bd90a2f9185 ] Make sure xHC completes the configure endpoint command and xhci driver sets the ring pointers correctly before we create the user readable debugfs file. In theory there was a small gap where a user could have read the debugfs file and cause a NULL pointer dereference error as ring pointer was not yet set, in practise we want this change to simplify the upcoming streams debugfs support. Fixes: 02b6fdc2a153 ("usb: xhci: Add debugfs interface for xHCI driver") Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200918131752.16488-10-mathias.nyman@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index f4cedcaee14b3..e534f524b7f87 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1915,8 +1915,6 @@ static int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev, ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index); trace_xhci_add_endpoint(ep_ctx); - xhci_debugfs_create_endpoint(xhci, virt_dev, ep_index); - xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n", (unsigned int) ep->desc.bEndpointAddress, udev->slot_id, @@ -2949,6 +2947,7 @@ static int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev) xhci_check_bw_drop_ep_streams(xhci, virt_dev, i); virt_dev->eps[i].ring = virt_dev->eps[i].new_ring; virt_dev->eps[i].new_ring = NULL; + xhci_debugfs_create_endpoint(xhci, virt_dev, i); } command_cleanup: kfree(command->completion);