{"id":"CVE-2025-39886","state":"PUBLISHED","title":"bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()","description":"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/","publishedAt":"2025-09-23T06:00:53.120Z","updatedAt":"2026-10-30T12:22:35.281Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"3e42431a705be8417ac5b696daa1dd43b3d27169","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"449682e76f32601f211816d3e2100bed87e67a4c","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"cd1fd26bb13473c1734e3026b2b97025a0a4087b","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"ac70cd446f83ccb25532b343919ab86eacdcd06a","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"6d78b4473cdb08b74662355a9e8510bde09c511e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/helpers.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.107","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.48","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.16.8","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/helpers.c"]}],"references":["https://git.kernel.org/stable/c/3e42431a705be8417ac5b696daa1dd43b3d27169","https://git.kernel.org/stable/c/449682e76f32601f211816d3e2100bed87e67a4c","https://git.kernel.org/stable/c/cd1fd26bb13473c1734e3026b2b97025a0a4087b","https://git.kernel.org/stable/c/ac70cd446f83ccb25532b343919ab86eacdcd06a","https://git.kernel.org/stable/c/6d78b4473cdb08b74662355a9e8510bde09c511e"],"weaknesses":[],"ingestedAt":"2026-10-30T12:40:04.423Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/39xxx/CVE-2025-39886.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39886","state":"PUBLISHED","datePublished":"2025-09-23T06:00:53.120Z","dateUpdated":"2026-10-30T12:22:35.281Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.145Z"},"containers":{"cna":{"title":"bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()","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/"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"3e42431a705be8417ac5b696daa1dd43b3d27169","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"449682e76f32601f211816d3e2100bed87e67a4c","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"cd1fd26bb13473c1734e3026b2b97025a0a4087b","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"ac70cd446f83ccb25532b343919ab86eacdcd06a","versionType":"git"},{"version":"b00628b1c7d595ae5b544e059c27b1f5828314b4","status":"affected","lessThan":"6d78b4473cdb08b74662355a9e8510bde09c511e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/helpers.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.15","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.107","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.48","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.16.8","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/helpers.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3e42431a705be8417ac5b696daa1dd43b3d27169"},{"url":"https://git.kernel.org/stable/c/449682e76f32601f211816d3e2100bed87e67a4c"},{"url":"https://git.kernel.org/stable/c/cd1fd26bb13473c1734e3026b2b97025a0a4087b"},{"url":"https://git.kernel.org/stable/c/ac70cd446f83ccb25532b343919ab86eacdcd06a"},{"url":"https://git.kernel.org/stable/c/6d78b4473cdb08b74662355a9e8510bde09c511e"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:22:35.281Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.6.107"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.12.48"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.16.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"6.17"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2025-39886","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-01-14T19:26:19.815693Z"}}}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-noinfo Not enough information"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-01-14T19:33:12.924Z"}}]}}}