{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.176-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.94-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.12-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  powerpc/time: Remove redundant preempt_disable|enable() calls from arch_irq_work_raise()  A kernel panic is observed when handling machine check exceptions from real mode.    BUG: Unable to handle kernel data access on read at 0xc00000006be21300   Oops: Kernel access of bad area, sig: 11 [#1]   MSR:  8000000000001003 \u003cSF,ME,RI,LE\u003e  CR: 88222248  XER: 00000005   CFAR: c00000000003ffc4 DAR: c00000006be21300 DSISR: 40000000 IRQMASK: 0   NIP [c000000000029e40] arch_irq_work_raise+0x10/0x70   LR [c00000000003ffc8] machine_check_queue_event+0xa8/0x150   Call Trace:   [c0000000179d3c70] [c00000000003ff64] machine_check_queue_event+0x44/0x150   [c0000000179d3d30] [c0000000000084e0] machine_check_early_common+0x1f0/0x2c0  The crash occurs because arch_irq_work_raise() calls preempt_disable() from machine check exception (MCE) handlers running in real mode. In this context, accessing the preempt_count can fault, leading to the panic.  The preempt_disable()/preempt_enable() pair in arch_irq_work_raise() was originally added by commit 0fe1ac48bef0 (\"powerpc/perf_event: Fix oops due to perf_event_do_pending call\") to avoid races while raising irq work from exception context.  Later, commit 471ba0e686cb (\"irq_work: Do not raise an IPI when queueing work on the local CPU\") added preemption protection in irq_work_queue() path, while commit 20b876918c06 (\"irq_work: Use per cpu atomics instead of regular atomics\") added equivalent protection in irq_work_queue_on() before reaching arch_irq_work_raise():    irq_work_queue() / irq_work_queue_on()     -\u003e preempt_disable()       -\u003e __irq_work_queue_local()         -\u003e irq_work_raise()           -\u003e arch_irq_work_raise()  As a result, callers other than mce_irq_work_raise() already execute with preemption disabled, making the additional preempt_disable()/preempt_enable() pair in arch_irq_work_raise() redundant.  The arch_irq_work_raise() function executes in NMI context when called from MCE handler. Hence we will not be preempted or scheduled out since we are in NMI context with MSR[EE]=0. Therefore, it is safe to remove the preempt_disable()/preempt_enable() calls from here.  Remove it to avoid accessing preempt_count from real mode context.  [Maddy: Fixed the commit title]",
  "id": "DEBIAN-CVE-2026-64214",
  "modified": "2026-09-14T16:47:41.813212458Z",
  "published": "2026-07-24T16:16:49.053Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-64214"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-64214"
  ]
}