CVE-2026-93219
Received Received - Intake

Clocksource Timer Synchronization Issue in Linux Kernel

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: clocksource/drivers/timer-sun4i: Advertise a real minimum delta sun4i_clkevt_next_event() compensates for the timer stop/start synchronization delay by programming evt - TIMER_SYNC_TICKS into the hardware interval register. The clockevent device currently advertises TIMER_SYNC_TICKS as min_delta_ticks, so the clockevents core is allowed to call set_next_event() with evt == TIMER_SYNC_TICKS. That programs a zero-tick interval. With oneshot/highres/nohz timer operation this can leave the next event stuck, which was observed as a boot hang on Allwinner D1 after the clockevents core started reusing forced minimum-delta events. Advertise one extra tick instead, so the smallest event accepted by the core still programs at least one hardware tick after the synchronization compensation.

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-25
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-93219
EUVD
EUVD-2026-85948

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a timer synchronization issue in the sun4i clocksource driver. The timer incorrectly advertises its minimum delta value, allowing a zero-tick interval to be programmed. This can cause the next timer event to get stuck, leading to a system boot hang on affected hardware like the Allwinner D1.

Detection Guidance

This vulnerability is specific to the Linux kernel's timer-sun4i driver and may cause system hangs. Detection requires checking the kernel version and the presence of the affected driver. Use 'uname -a' to check the kernel version and 'lsmod | grep sun4i' to see if the driver is loaded. If the system uses an Allwinner D1 SoC, it may be affected.

Impact Analysis

If you use a system with an Allwinner D1 or similar hardware running a vulnerable Linux kernel, this flaw could cause the system to hang during boot. It may also lead to timer-related instability or crashes in systems using oneshot, highres, or nohz timer modes.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a low-level kernel timer issue causing potential boot hangs on specific hardware, with no documented impact on data protection or privacy requirements.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this issue. Check with your distribution's package manager for updates (e.g., 'apt upgrade' or 'yum update'). If an update is unavailable, avoid using the sun4i timer driver or disable it via kernel parameters.

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