Description
In the Linux kernel, the following vulnerability has been resolved:
HID: appletb-kbd: run inactivity autodim from workqueues
The autodim code in hid-appletb-kbd takes backlight_device->ops_lock
via backlight_device_set_brightness() -> mutex_lock() from two
different atomic contexts:
* appletb_inactivity_timer() is a struct timer_list callback, so it
runs in softirq context. Every expiry triggers
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
Call Trace:
<IRQ>
__might_resched
__mutex_lock
backlight_device_set_brightness
appletb_inactivity_timer
call_timer_fn
run_timer_softirq
* reset_inactivity_timer() is called from appletb_kbd_hid_event() and
appletb_kbd_inp_event(). On real USB hardware these run in
softirq/IRQ context (URB completion and input-event dispatch).
When the Touch Bar has already been dimmed or turned off, the
reset path calls backlight_device_set_brightness() directly to
restore brightness, producing the same warning.
Both call sites hit the same mutex_lock()-from-atomic bug. Fix them
together by moving the blocking work onto the system workqueue:
* Convert the inactivity timer from struct timer_list to
struct delayed_work; the callback (appletb_inactivity_work) now
runs in process context where mutex_lock() is legal.
* Add a dedicated struct work_struct restore_brightness_work and have
reset_inactivity_timer() schedule it instead of calling
backlight_device_set_brightness() directly.
Cancel both works synchronously during driver tear-down alongside the
existing backlight reference drop.
The semantics are unchanged (same delays, same state transitions on
dim, turn-off and user activity); only the execution context of the
sleeping call changes. The timer field and callback are renamed to
match their new type; reset_inactivity_timer() keeps its name because
it is invoked from input event paths that read naturally as "reset
the inactivity timer".
HID: appletb-kbd: run inactivity autodim from workqueues
The autodim code in hid-appletb-kbd takes backlight_device->ops_lock
via backlight_device_set_brightness() -> mutex_lock() from two
different atomic contexts:
* appletb_inactivity_timer() is a struct timer_list callback, so it
runs in softirq context. Every expiry triggers
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
Call Trace:
<IRQ>
__might_resched
__mutex_lock
backlight_device_set_brightness
appletb_inactivity_timer
call_timer_fn
run_timer_softirq
* reset_inactivity_timer() is called from appletb_kbd_hid_event() and
appletb_kbd_inp_event(). On real USB hardware these run in
softirq/IRQ context (URB completion and input-event dispatch).
When the Touch Bar has already been dimmed or turned off, the
reset path calls backlight_device_set_brightness() directly to
restore brightness, producing the same warning.
Both call sites hit the same mutex_lock()-from-atomic bug. Fix them
together by moving the blocking work onto the system workqueue:
* Convert the inactivity timer from struct timer_list to
struct delayed_work; the callback (appletb_inactivity_work) now
runs in process context where mutex_lock() is legal.
* Add a dedicated struct work_struct restore_brightness_work and have
reset_inactivity_timer() schedule it instead of calling
backlight_device_set_brightness() directly.
Cancel both works synchronously during driver tear-down alongside the
existing backlight reference drop.
The semantics are unchanged (same delays, same state transitions on
dim, turn-off and user activity); only the execution context of the
sleeping call changes. The timer field and callback are renamed to
match their new type; reset_inactivity_timer() keeps its name because
it is invoked from input event paths that read naturally as "reset
the inactivity timer".
Published:
2026-05-28
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Thu, 28 May 2026 10:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: HID: appletb-kbd: run inactivity autodim from workqueues The autodim code in hid-appletb-kbd takes backlight_device->ops_lock via backlight_device_set_brightness() -> mutex_lock() from two different atomic contexts: * appletb_inactivity_timer() is a struct timer_list callback, so it runs in softirq context. Every expiry triggers BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591 Call Trace: <IRQ> __might_resched __mutex_lock backlight_device_set_brightness appletb_inactivity_timer call_timer_fn run_timer_softirq * reset_inactivity_timer() is called from appletb_kbd_hid_event() and appletb_kbd_inp_event(). On real USB hardware these run in softirq/IRQ context (URB completion and input-event dispatch). When the Touch Bar has already been dimmed or turned off, the reset path calls backlight_device_set_brightness() directly to restore brightness, producing the same warning. Both call sites hit the same mutex_lock()-from-atomic bug. Fix them together by moving the blocking work onto the system workqueue: * Convert the inactivity timer from struct timer_list to struct delayed_work; the callback (appletb_inactivity_work) now runs in process context where mutex_lock() is legal. * Add a dedicated struct work_struct restore_brightness_work and have reset_inactivity_timer() schedule it instead of calling backlight_device_set_brightness() directly. Cancel both works synchronously during driver tear-down alongside the existing backlight reference drop. The semantics are unchanged (same delays, same state transitions on dim, turn-off and user activity); only the execution context of the sleeping call changes. The timer field and callback are renamed to match their new type; reset_inactivity_timer() keeps its name because it is invoked from input event paths that read naturally as "reset the inactivity timer". | |
| Title | HID: appletb-kbd: run inactivity autodim from workqueues | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-28T09:40:18.687Z
Reserved: 2026-05-13T15:03:33.104Z
Link: CVE-2026-46202
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-05-28T10:16:35.860
Modified: 2026-05-28T10:16:35.860
Link: CVE-2026-46202
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.