CVE-2026-31754

In the Linux kernel, the following vulnerability has been resolved:

usb: cdns3: gadget: fix state inconsistency on gadget init failure

When cdns3_gadget_start() fails, the DRD hardware is left in gadget mode

while software state remains INACTIVE, creating hardware/software state

inconsistency.

When switching to host mode via sysfs:

echo host > /sys/class/usb_role/13180000.usb-role-switch/role

The role state is not set to CDNS_ROLE_STATE_ACTIVE due to the error,

so cdns_role_stop() skips cleanup because state is still INACTIVE.

This violates the DRD controller design specification (Figure22),

which requires returning to idle state before switching roles.

This leads to a synchronous external abort in xhci_gen_setup() when

setting up the host controller:

[ 516.440698] configfs-gadget 13180000.usb: failed to start g1: -19

[ 516.442035] cdns-usb3 13180000.usb: Failed to add gadget

[ 516.443278] cdns-usb3 13180000.usb: set role 2 has failed

...

[ 1301.375722] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller

[ 1301.377716] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP

[ 1301.382485] pc : xhci_gen_setup+0xa4/0x408

[ 1301.393391] backtrace:

...

xhci_gen_setup+0xa4/0x408 <-- CRASH

xhci_plat_setup+0x44/0x58

usb_add_hcd+0x284/0x678

...

cdns_role_set+0x9c/0xbc <-- Role switch

Fix by calling cdns_drd_gadget_off() in the error path to properly

clean up the DRD gadget state.