{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2025-39900",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2025-39900"
  ],
  "published": "2025-10-01T07:43:27Z",
  "summary": "net_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y\n\nsyzbot reported a WARNING in est_timer() [1]\n\nProblem here is that with CONFIG_PREEMPT_RT=y, timer callbacks\ncan be preempted.\n\nAdopt preempt_disable_nested()/preempt_enable_nested() to fix this.\n\n[1]\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 __seqprop_assert include/linux/seqlock.h:221 [inline]\n WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\nModules linked in:\nCPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025\n RIP: 0010:__seqprop_assert include/linux/seqlock.h:221 [inline]\n RIP: 0010:est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93\nCall Trace:\n <TASK>\n  call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747\n  expire_timers kernel/time/timer.c:1798 [inline]\n  __run_timers kernel/time/timer.c:2372 [inline]\n  __run_timer_base+0x648/0x970 kernel/time/timer.c:2384\n  run_timer_base kernel/time/timer.c:2393 [inline]\n  run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403\n  handle_softirqs+0x22c/0x710 kernel/softirq.c:579\n  __do_softirq kernel/softirq.c:613 [inline]\n  run_ktimerd+0xcf/0x190 kernel/softirq.c:1043\n  smpboot_thread_fn+0x53f/0xa60 kernel/smpboot.c:160\n  kthread+0x70e/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n </TASK>",
  "affected": [
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      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
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        "1:6.12.25-1+rpt1",
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  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-39900"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a22ec2ee824be30803068a52f78f7ffe3bc879fb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e79923824c48b930609680be04cb29253fc4a17d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9f74c0ea9b26d1505d55b61e36b1623dd347e1d1"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-05-12T04:54:46Z"
  }
}