CVE-2025-39886

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()

Currently, calling bpf_map_kmalloc_node() from __bpf_async_init() can

cause various locking issues; see the following stack trace (edited for

style) as one example:

...

[10.011566] do_raw_spin_lock.cold

[10.011570] try_to_wake_up (5) double-acquiring the same

[10.011575] kick_pool rq_lock, causing a hardlockup

[10.011579] __queue_work

[10.011582] queue_work_on

[10.011585] kernfs_notify

[10.011589] cgroup_file_notify

[10.011593] try_charge_memcg (4) memcg accounting raises an

[10.011597] obj_cgroup_charge_pages MEMCG_MAX event

[10.011599] obj_cgroup_charge_account

[10.011600] __memcg_slab_post_alloc_hook

[10.011603] __kmalloc_node_noprof

...

[10.011611] bpf_map_kmalloc_node

[10.011612] __bpf_async_init

[10.011615] bpf_timer_init (3) BPF calls bpf_timer_init()

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References