{"schema_version":"1.7.5","id":"CVE-2026-31667","published":"2026-04-24T14:45:15.937Z","modified":"2026-07-22T18:14:59.988195320Z","related":["SUSE-SU-2026:2068-1","SUSE-SU-2026:3130-1","SUSE-SU-2026:3166-1"],"summary":"Input: uinput - fix circular locking dependency with ff-core","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nInput: uinput - fix circular locking dependency with ff-core\n\nA lockdep circular locking dependency warning can be triggered\nreproducibly when using a force-feedback gamepad with uinput (for\nexample, playing ELDEN RING under Wine with a Flydigi Vader 5\ncontroller):\n\n  ff->mutex -> udev->mutex -> input_mutex -> dev->mutex -> ff->mutex\n\nThe cycle is caused by four lock acquisition paths:\n\n1. ff upload: input_ff_upload() holds ff->mutex and calls\n   uinput_dev_upload_effect() -> uinput_request_submit() ->\n   uinput_request_send(), which acquires udev->mutex.\n\n2. device create: uinput_ioctl_handler() holds udev->mutex and calls\n   uinput_create_device() -> input_register_device(), which acquires\n   input_mutex.\n\n3. device register: input_register_device() holds input_mutex and\n   calls kbd_connect() -> input_register_handle(), which acquires\n   dev->mutex.\n\n4. evdev release: evdev_release() calls input_flush_device() under\n   dev->mutex, which calls input_ff_flush() acquiring ff->mutex.\n\nFix this by introducing a new state_lock spinlock to protect\nudev->state and udev->dev access in uinput_request_send() instead of\nacquiring udev->mutex.  The function only needs to atomically check\ndevice state and queue an input event into the ring buffer via\nuinput_dev_event() -- both operations are safe under a spinlock\n(ktime_get_ts64() and wake_up_interruptible() do not sleep).  This\nbreaks the ff->mutex -> udev->mutex link since a spinlock is a leaf in\nthe lock ordering and cannot form cycles with mutexes.\n\nTo keep state transitions visible to uinput_request_send(), protect\nwrites to udev->state in uinput_create_device() and\nuinput_destroy_device() with the same state_lock spinlock.\n\nAdditionally, move init_completion(&request->done) from\nuinput_request_send() to uinput_request_submit() before\nuinput_request_reserve_slot().  Once the slot is allocated,\nuinput_flush_requests() may call complete() on it at any time from\nthe destroy path, so the completion must be initialised before the\nrequest becomes visible.\n\nLock ordering after the fix:\n\n  ff->mutex -> state_lock (spinlock, leaf)\n  udev->mutex -> state_lock (spinlock, leaf)\n  udev->mutex -> input_mutex -> dev->mutex -> ff->mutex (no back-edge)","affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"ff462551235d8d7d843a005950bc90924fcedede"},{"fixed":"71a9729f412e2c692a35c542e14b706fb342927f"},{"fixed":"271ee71a1917b89f6d73ec82dd091c33d92ee617"},{"fixed":"974f7b138c3a96dd5cd53d1b33409cd7b2229dc6"},{"fixed":"546c18a14924eb521fe168d916d7ce28f1e13c1d"},{"fixed":"a3d6c9c053c9c605651508569230ead633b13f76"},{"fixed":"1e09dfbb4f5d20ee111f92325a00f85778a5f328"},{"fixed":"1534661043c434b81cfde26b97a2fb2460329cf0"},{"fixed":"4cda78d6f8bf2b700529f2fbccb994c3e826d7c2"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31667.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.19"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.169"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.135"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.82"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.23"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31667.json"}}],"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1534661043c434b81cfde26b97a2fb2460329cf0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1e09dfbb4f5d20ee111f92325a00f85778a5f328"},{"type":"WEB","url":"https://git.kernel.org/stable/c/271ee71a1917b89f6d73ec82dd091c33d92ee617"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4cda78d6f8bf2b700529f2fbccb994c3e826d7c2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/546c18a14924eb521fe168d916d7ce28f1e13c1d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/71a9729f412e2c692a35c542e14b706fb342927f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/974f7b138c3a96dd5cd53d1b33409cd7b2229dc6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3d6c9c053c9c605651508569230ead633b13f76"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31667.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31667"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31667.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}