{
  "cveId": "CVE-2022-49540",
  "url": "https://patchblox.com/security/cve/CVE-2022-49540",
  "summary": "CVE-2022-49540 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49540, released February 26, 2025. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  rcu-tasks: Fix race in schedule and flush work...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  rcu-tasks: Fix race in schedule and flush work  While booting secondary CPUs, cpus_read_[lock/unlock] is not keeping online cpumask stable. The transient online mask results in below calltrace.  [    0.324121] CPU1: Booted secondary processor 0x0000000001 [0x410fd083] [    0.346652] Detected PIPT I-cache on CPU2 [    0.347212] CPU2: Booted secondary processor 0x0000000002 [0x410fd083] [    0.377255] Detected PIPT I-cache on CPU3 [    0.377823] CPU3: Booted secondary processor 0x0000000003 [0x410fd083] [    0.379040] ------------[ cut here ]------------ [    0.383662] WARNING: CPU: 0 PID: 10 at kernel/workqueue.c:3084 __flush_work\u002B0x12c/0x138 [    0.384850] Modules linked in: [    0.385403] CPU: 0 PID: 10 Comm: rcu_tasks_rude_ Not tainted 5.17.0-rc3-v8\u002B #13 [    0.386473] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT) [    0.387289] pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [    0.388308] pc : __flush_work\u002B0x12c/0x138 [    0.388970] lr : __flush_work\u002B0x80/0x138 [    0.389620] sp : ffffffc00aaf3c60 [    0.390139] x29: ffffffc00aaf3d20 x28: ffffffc009c16af0 x27: ffffff80f761df48 [    0.391316] x26: 0000000000000004 x25: 0000000000000003 x24: 0000000000000100 [    0.392493] x23: ffffffffffffffff x22: ffffffc009c16b10 x21: ffffffc009c16b28 [    0.393668] x20: ffffffc009e53861 x19: ffffff80f77fbf40 x18: 00000000d744fcc9 [    0.394842] x17: 000000000000000b x16: 00000000000001c2 x15: ffffffc009e57550 [    0.396016] x14: 0000000000000000 x13: ffffffffffffffff x12: 0000000100000000 [    0.397190] x11: 0000000000000462 x10: ffffff8040258008 x9 : 0000000100000000 [    0.398364] x8 : 0000000000000000 x7 : ffffffc0093c8bf4 x6 : 0000000000000000 [    0.399538] x5 : 0000000000000000 x4 : ffffffc00a976e40 x3 : ffffffc00810444c [    0.400711] x2 : 0000000000000004 x1 : 0000000000000000 x0 : 0000000000000000 [    0.401886] Call trace: [    0.402309]  __flush_work\u002B0x12c/0x138 [    0.402941]  schedule_on_each_cpu\u002B0x228/0x278 [    0.403693]  rcu_tasks_rude_wait_gp\u002B0x130/0x144 [    0.404502]  rcu_tasks_kthread\u002B0x220/0x254 [    0.405264]  kthread\u002B0x174/0x1ac [    0.405837]  ret_from_fork\u002B0x10/0x20 [    0.406456] irq event stamp: 102 [    0.406966] hardirqs last  enabled at (101): [\u003Cffffffc0093c8468\u003E] _raw_spin_unlock_irq\u002B0x78/0xb4 [    0.408304] hardirqs last disabled at (102): [\u003Cffffffc0093b8270\u003E] el1_dbg\u002B0x24/0x5c [    0.409410] softirqs last  enabled at (54): [\u003Cffffffc0081b80c8\u003E] local_bh_enable\u002B0xc/0x2c [    0.410645] softirqs last disabled at (50): [\u003Cffffffc0081b809c\u003E] local_bh_disable\u002B0xc/0x2c [    0.411890] ---[ end trace 0000000000000000 ]--- [    0.413000] smp: Brought up 1 node, 4 CPUs [    0.413762] SMP: Total of 4 processors activated. [    0.414566] CPU features: detected: 32-bit EL0 Support [    0.415414] CPU features: detected: 32-bit EL1 Support [    0.416278] CPU features: detected: CRC32 instructions [    0.447021] Callback from call_rcu_tasks_rude() invoked. [    0.506693] Callback from call_rcu_tasks() invoked.  This commit therefore fixes this issue by applying a single-CPU optimization to the RCU Tasks Rude grace-period process.  The key point here is that the purpose of this RCU flavor is to force a schedule on each online CPU since some past event.  But the rcu_tasks_rude_wait_gp() function runs in the context of the RCU Tasks Rude\u0027s grace-period kthread, so there must already have been a context switch on the current CPU since the call to either synchronize_rcu_tasks_rude() or call_rcu_tasks_rude(). So if there is only a single CPU online, RCU Tasks Rude\u0027s grace-period kthread does not need to anything at all.  It turns out that the rcu_tasks_rude_wait_gp() function\u0027s call to schedule_on_each_cpu() causes problems during early boot.  During that time, there is only one online CPU, namely the boot CPU.  Therefore, applying this single-CPU optimization fixes early-boot instances of this problem.",
  "published": "2025-02-26T07:01:29Z",
  "severity": "medium",
  "cvss": 4.7,
  "cvssVector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.00188,
  "epssPercentile": 0.08493,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.18.5-1",
      "fix": "DEBIAN-CVE-2022-49540",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49540",
      "released": "2025-02-26T07:01:29Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.18.5-1",
      "fix": "DEBIAN-CVE-2022-49540",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49540",
      "released": "2025-02-26T07:01:29Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.18.5-1",
      "fix": "DEBIAN-CVE-2022-49540",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49540",
      "released": "2025-02-26T07:01:29Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}