{
  "cveId": "CVE-2022-49783",
  "url": "https://patchblox.com/security/cve/CVE-2022-49783",
  "summary": "CVE-2022-49783 is fixed in linux on 1 platform, first by DEBIAN-CVE-2022-49783, released May 1, 2025. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  x86/fpu: Drop fpregs lock before inheriting FPU...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  x86/fpu: Drop fpregs lock before inheriting FPU permissions  Mike Galbraith reported the following against an old fork of preempt-rt but the same issue also applies to the current preempt-rt tree.     BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46    in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: systemd    preempt_count: 1, expected: 0    RCU nest depth: 0, expected: 0    Preemption disabled at:    fpu_clone    CPU: 6 PID: 1 Comm: systemd Tainted: G            E       (unreleased)    Call Trace:     \u003CTASK\u003E     dump_stack_lvl     ? fpu_clone     __might_resched     rt_spin_lock     fpu_clone     ? copy_thread     ? copy_process     ? shmem_alloc_inode     ? kmem_cache_alloc     ? kernel_clone     ? __do_sys_clone     ? do_syscall_64     ? __x64_sys_rt_sigprocmask     ? syscall_exit_to_user_mode     ? do_syscall_64     ? syscall_exit_to_user_mode     ? do_syscall_64     ? syscall_exit_to_user_mode     ? do_syscall_64     ? exc_page_fault     ? entry_SYSCALL_64_after_hwframe     \u003C/TASK\u003E  Mike says:    The splat comes from fpu_inherit_perms() being called under fpregs_lock(),   and us reaching the spin_lock_irq() therein due to fpu_state_size_dynamic()   returning true despite static key __fpu_state_size_dynamic having never   been enabled.  Mike\u0027s assessment looks correct. fpregs_lock on a PREEMPT_RT kernel disables preemption so calling spin_lock_irq() in fpu_inherit_perms() is unsafe. This problem exists since commit    9e798e9aa14c (\u0022x86/fpu: Prepare fpu_clone() for dynamically enabled features\u0022).  Even though the original bug report should not have enabled the paths at all, the bug still exists.  fpregs_lock is necessary when editing the FPU registers or a task\u0027s FP state but it is not necessary for fpu_inherit_perms(). The only write of any FP state in fpu_inherit_perms() is for the new child which is not running yet and cannot context switch or be borrowed by a kernel thread yet. Hence, fpregs_lock is not protecting anything in the new child until clone() completes and can be dropped earlier. The siglock still needs to be acquired by fpu_inherit_perms() as the read of the parent\u0027s permissions has to be serialised.    [ bp: Cleanup splat. ]",
  "published": "2025-05-01T15:16:01Z",
  "severity": "medium",
  "cvss": 5.5,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.0017,
  "epssPercentile": 0.06465,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.0.10-1",
      "fix": "DEBIAN-CVE-2022-49783",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49783",
      "released": "2025-05-01T15:16:01Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.0.10-1",
      "fix": "DEBIAN-CVE-2022-49783",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49783",
      "released": "2025-05-01T15:16:01Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "6.0.10-1",
      "fix": "DEBIAN-CVE-2022-49783",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2022-49783",
      "released": "2025-05-01T15:16:01Z"
    }
  ],
  "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"
  }
}