This is a note to let you know that I've just added the patch titled USB: core: Fix access violation during port device removal to the 6.6-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: usb-core-fix-access-violation-during-port-device-removal.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a4b46d450c49f32e9d4247b421e58083fde304ce Mon Sep 17 00:00:00 2001 From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Date: Thu, 18 Apr 2024 11:13:13 -0400 Subject: USB: core: Fix access violation during port device removal From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> commit a4b46d450c49f32e9d4247b421e58083fde304ce upstream. Testing with KASAN and syzkaller revealed a bug in port.c:disable_store(): usb_hub_to_struct_hub() can return NULL if the hub that the port belongs to is concurrently removed, but the function does not check for this possibility before dereferencing the returned value. It turns out that the first dereference is unnecessary, since hub->intfdev is the parent of the port device, so it can be changed easily. Adding a check for hub == NULL prevents further problems. The same bug exists in the disable_show() routine, and it can be fixed the same way. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Reported-and-tested-by: Yue Sun <samsun1006219@xxxxxxxxx> Reported-by: xingwei lee <xrivendell7@xxxxxxxxx> Link: https://lore.kernel.org/linux-usb/CAEkJfYON+ry7xPx=AiLR9jzUNT+i_Va68ACajOC3HoacOfL1ig@xxxxxxxxxxxxxx/ Fixes: f061f43d7418 ("usb: hub: port: add sysfs entry to switch port power") CC: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> CC: stable@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/393aa580-15a5-44ca-ad3b-6462461cd313@xxxxxxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/core/port.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/drivers/usb/core/port.c +++ b/drivers/usb/core/port.c @@ -50,13 +50,15 @@ static ssize_t disable_show(struct devic struct usb_port *port_dev = to_usb_port(dev); struct usb_device *hdev = to_usb_device(dev->parent->parent); struct usb_hub *hub = usb_hub_to_struct_hub(hdev); - struct usb_interface *intf = to_usb_interface(hub->intfdev); + struct usb_interface *intf = to_usb_interface(dev->parent); int port1 = port_dev->portnum; u16 portstatus, unused; bool disabled; int rc; struct kernfs_node *kn; + if (!hub) + return -ENODEV; hub_get(hub); rc = usb_autopm_get_interface(intf); if (rc < 0) @@ -100,12 +102,14 @@ static ssize_t disable_store(struct devi struct usb_port *port_dev = to_usb_port(dev); struct usb_device *hdev = to_usb_device(dev->parent->parent); struct usb_hub *hub = usb_hub_to_struct_hub(hdev); - struct usb_interface *intf = to_usb_interface(hub->intfdev); + struct usb_interface *intf = to_usb_interface(dev->parent); int port1 = port_dev->portnum; bool disabled; int rc; struct kernfs_node *kn; + if (!hub) + return -ENODEV; rc = kstrtobool(buf, &disabled); if (rc) return rc; Patches currently in stable-queue which might be from stern@xxxxxxxxxxxxxxxxxxx are queue-6.6/usb-ohci-prevent-missed-ohci-interrupts.patch queue-6.6/usb-core-fix-access-violation-during-port-device-removal.patch queue-6.6/usb-fix-regression-caused-by-invalid-ep0-maxpacket-in-virtual-superspeed-device.patch