fkie_cve-2025-39886
Vulnerability from fkie_nvd
Published
2025-09-23 06:15
Modified
2025-09-23 06:15
Severity ?
Summary
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()
[10.011617] bpf_prog_xxxxxxxxxxxxxxxx_fcg_runnable
[10.011619] bpf__sched_ext_ops_runnable
[10.011620] enqueue_task_scx (2) BPF runs with rq_lock held
[10.011622] enqueue_task
[10.011626] ttwu_do_activate
[10.011629] sched_ttwu_pending (1) grabs rq_lock
...
The above was reproduced on bpf-next (b338cf849ec8) by modifying
./tools/sched_ext/scx_flatcg.bpf.c to call bpf_timer_init() during
ops.runnable(), and hacking the memcg accounting code a bit to make
a bpf_timer_init() call more likely to raise an MEMCG_MAX event.
We have also run into other similar variants (both internally and on
bpf-next), including double-acquiring cgroup_file_kn_lock, the same
worker_pool::lock, etc.
As suggested by Shakeel, fix this by using __GFP_HIGH instead of
GFP_ATOMIC in __bpf_async_init(), so that e.g. if try_charge_memcg()
raises an MEMCG_MAX event, we call __memcg_memory_event() with
@allow_spinning=false and avoid calling cgroup_file_notify() there.
Depends on mm patch
"memcg: skip cgroup_file_notify if spinning is not allowed":
https://lore.kernel.org/bpf/20250905201606.66198-1-shakeel.butt@linux.dev/
v0 approach s/bpf_map_kmalloc_node/bpf_mem_alloc/
https://lore.kernel.org/bpf/20250905061919.439648-1-yepeilin@google.com/
v1 approach:
https://lore.kernel.org/bpf/20250905234547.862249-1-yepeilin@google.com/
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()\n\nCurrently, calling bpf_map_kmalloc_node() from __bpf_async_init() can\ncause various locking issues; see the following stack trace (edited for\nstyle) as one example:\n\n...\n [10.011566] do_raw_spin_lock.cold\n [10.011570] try_to_wake_up (5) double-acquiring the same\n [10.011575] kick_pool rq_lock, causing a hardlockup\n [10.011579] __queue_work\n [10.011582] queue_work_on\n [10.011585] kernfs_notify\n [10.011589] cgroup_file_notify\n [10.011593] try_charge_memcg (4) memcg accounting raises an\n [10.011597] obj_cgroup_charge_pages MEMCG_MAX event\n [10.011599] obj_cgroup_charge_account\n [10.011600] __memcg_slab_post_alloc_hook\n [10.011603] __kmalloc_node_noprof\n...\n [10.011611] bpf_map_kmalloc_node\n [10.011612] __bpf_async_init\n [10.011615] bpf_timer_init (3) BPF calls bpf_timer_init()\n [10.011617] bpf_prog_xxxxxxxxxxxxxxxx_fcg_runnable\n [10.011619] bpf__sched_ext_ops_runnable\n [10.011620] enqueue_task_scx (2) BPF runs with rq_lock held\n [10.011622] enqueue_task\n [10.011626] ttwu_do_activate\n [10.011629] sched_ttwu_pending (1) grabs rq_lock\n...\n\nThe above was reproduced on bpf-next (b338cf849ec8) by modifying\n./tools/sched_ext/scx_flatcg.bpf.c to call bpf_timer_init() during\nops.runnable(), and hacking the memcg accounting code a bit to make\na bpf_timer_init() call more likely to raise an MEMCG_MAX event.\n\nWe have also run into other similar variants (both internally and on\nbpf-next), including double-acquiring cgroup_file_kn_lock, the same\nworker_pool::lock, etc.\n\nAs suggested by Shakeel, fix this by using __GFP_HIGH instead of\nGFP_ATOMIC in __bpf_async_init(), so that e.g. if try_charge_memcg()\nraises an MEMCG_MAX event, we call __memcg_memory_event() with\n@allow_spinning=false and avoid calling cgroup_file_notify() there.\n\nDepends on mm patch\n\"memcg: skip cgroup_file_notify if spinning is not allowed\":\nhttps://lore.kernel.org/bpf/20250905201606.66198-1-shakeel.butt@linux.dev/\n\nv0 approach s/bpf_map_kmalloc_node/bpf_mem_alloc/\nhttps://lore.kernel.org/bpf/20250905061919.439648-1-yepeilin@google.com/\nv1 approach:\nhttps://lore.kernel.org/bpf/20250905234547.862249-1-yepeilin@google.com/"
}
],
"id": "CVE-2025-39886",
"lastModified": "2025-09-23T06:15:48.680",
"metrics": {},
"published": "2025-09-23T06:15:48.680",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/449682e76f32601f211816d3e2100bed87e67a4c"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6d78b4473cdb08b74662355a9e8510bde09c511e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ac70cd446f83ccb25532b343919ab86eacdcd06a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cd1fd26bb13473c1734e3026b2b97025a0a4087b"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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