CVE-2026-53326: debugobjects: Don't call fill_pool() in early boot hardirq context
In the Linux kernel, the following vulnerability has been resolved:
debugobjects: Don't call fillpool() in early boot hardirq context
When booting a debug PREEMPTRT kernel on an ARM64 system, a "inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage" lockdep warning message was reported to the console.
During early boot, interrupts are enabled before the scheduler is enabled. In this window (before SYSTEMSCHEDULING is set) interrupts can fire and in the hard interrupt context handler attempt to fill the pool
This can lead to a deadlock when the interrupt occurred when the interrupt hits a region which holds a lock that is required to be taken in the allocation path.
Add a new canfillpool() helper and reorder the exception rule and forbid this scenario by excluding allocations from hard interrupt context.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Modify kernel behavior so that debugobjects does not call fill_pool() in early boot hardirq context; exclude allocations from hard interrupt context during the early boot window (before SYSTEM_SCHEDULING is set) to avoid the lock-dependent deadlock scenario described.
Linux kernel (debugobjects / allocator) allocation behavior in hard interrupt (hardirq) context during early boot = Exclude allocations from hard interrupt context before SYSTEM_SCHEDULING is set
Event History
Frequently Asked Questions
What is the severity of CVE-2026-53326?
CVE-2026-53326 has a risk rating of 25.
How do I fix CVE-2026-53326?
To fix CVE-2026-53326, upgrade your Linux kernel to the latest patched version available.
What systems are affected by CVE-2026-53326?
CVE-2026-53326 affects ARM64 systems running a debug PREEMPT_RT kernel.
What type of warning does CVE-2026-53326 generate?
CVE-2026-53326 generates a 'inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage' warning message.
Is CVE-2026-53326 only relevant for debugging purposes?
Yes, CVE-2026-53326 primarily impacts the functionality of debugging features in the Linux kernel.