fkie_cve-2025-40163
Vulnerability from fkie_nvd
Published
2025-11-12 11:15
Modified
2025-11-12 16:19
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: sched/deadline: Stop dl_server before CPU goes offline IBM CI tool reported kernel warning[1] when running a CPU removal operation through drmgr[2]. i.e "drmgr -c cpu -r -q 1" WARNING: CPU: 0 PID: 0 at kernel/sched/cpudeadline.c:219 cpudl_set+0x58/0x170 NIP [c0000000002b6ed8] cpudl_set+0x58/0x170 LR [c0000000002b7cb8] dl_server_timer+0x168/0x2a0 Call Trace: [c000000002c2f8c0] init_stack+0x78c0/0x8000 (unreliable) [c0000000002b7cb8] dl_server_timer+0x168/0x2a0 [c00000000034df84] __hrtimer_run_queues+0x1a4/0x390 [c00000000034f624] hrtimer_interrupt+0x124/0x300 [c00000000002a230] timer_interrupt+0x140/0x320 Git bisects to: commit 4ae8d9aa9f9d ("sched/deadline: Fix dl_server getting stuck") This happens since: - dl_server hrtimer gets enqueued close to cpu offline, when kthread_park enqueues a fair task. - CPU goes offline and drmgr removes it from cpu_present_mask. - hrtimer fires and warning is hit. Fix it by stopping the dl_server before CPU is marked dead. [1]: https://lore.kernel.org/all/8218e149-7718-4432-9312-f97297c352b9@linux.ibm.com/ [2]: https://github.com/ibm-power-utilities/powerpc-utils/tree/next/src/drmgr [sshegde: wrote the changelog and tested it]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ab6c0f158508bb16d483add70b73a73f95651c33
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ee6e44dfe6e50b4a5df853d933a96bdff5309e6e
Impacted products
Vendor Product Version


To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/deadline: Stop dl_server before CPU goes offline\n\nIBM CI tool reported kernel warning[1] when running a CPU removal\noperation through drmgr[2]. i.e \"drmgr -c cpu -r -q 1\"\n\nWARNING: CPU: 0 PID: 0 at kernel/sched/cpudeadline.c:219 cpudl_set+0x58/0x170\nNIP [c0000000002b6ed8] cpudl_set+0x58/0x170\nLR [c0000000002b7cb8] dl_server_timer+0x168/0x2a0\nCall Trace:\n[c000000002c2f8c0] init_stack+0x78c0/0x8000 (unreliable)\n[c0000000002b7cb8] dl_server_timer+0x168/0x2a0\n[c00000000034df84] __hrtimer_run_queues+0x1a4/0x390\n[c00000000034f624] hrtimer_interrupt+0x124/0x300\n[c00000000002a230] timer_interrupt+0x140/0x320\n\nGit bisects to: commit 4ae8d9aa9f9d (\"sched/deadline: Fix dl_server getting stuck\")\n\nThis happens since:\n- dl_server hrtimer gets enqueued close to cpu offline, when\n  kthread_park enqueues a fair task.\n- CPU goes offline and drmgr removes it from cpu_present_mask.\n- hrtimer fires and warning is hit.\n\nFix it by stopping the dl_server before CPU is marked dead.\n\n[1]: https://lore.kernel.org/all/8218e149-7718-4432-9312-f97297c352b9@linux.ibm.com/\n[2]: https://github.com/ibm-power-utilities/powerpc-utils/tree/next/src/drmgr\n\n[sshegde: wrote the changelog and tested it]"
    }
  ],
  "id": "CVE-2025-40163",
  "lastModified": "2025-11-12T16:19:12.850",
  "metrics": {},
  "published": "2025-11-12T11:15:46.517",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ab6c0f158508bb16d483add70b73a73f95651c33"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ee6e44dfe6e50b4a5df853d933a96bdff5309e6e"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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