Executive brief
A vulnerability was identified in the Linux kernel's memory management system. Under specific conditions involving high-priority system interrupts (NMI), the system could attempt to access a locking mechanism that is not designed for such contexts. This can lead to a system deadlock, causing the operating system to hang or crash, resulting in a denial of service.
Technical details
A deadlock condition exists in the Linux kernel's mm/slab component due to unsafe locking in NMI contexts. The function get_from_any_partial() (or get_any_partial() in some versions) accesses current->mems_allowed_seq, which uses a seqcount_spinlock_t. Because seqcount_t is not NMI-safe, an interrupt occurring while the write-side critical section is active can lead to an inconsistent lock state and a kernel deadlock. The fix involves checking GFP flags to ensure the kernel does not attempt to access the sequence counter or retry the operation when spinning is not allowed (e.g., in NMI contexts). Patches have been released for various stable branches of the Linux kernel.
Affected products
- Linux Linux Kernel 6.19-rc5 and earlier versions
Timeline
- 2026-02-10: patched: Initial fix committed to mainline kernel tree.
- 2026-05-08: disclosed: CVE-2026-43285 published.