CVE-2024-38613: Linux kernel · m68k: Fix spinlock race in kernel thread creation
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 4.7 Medium · fixed in 5.4.0-1130.140~18.04.1 : update Linux kernel when convenient.
Data as of 28 Oct 2026, 10:59 UTC
- Patch
- Available – fixed in 5.4.0-1130.140~18.04.1, 5.4.0-1135.142~18.04.1, 5.4.0-1134.143~18.04.1 +73
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jun 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-6949-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6952-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6953-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6955-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6949-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6952-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6979-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7007-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-ibmpkg:deb/ubuntu/linux-ibm?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
In the Linux kernel, the following vulnerability has been resolved: m68k: Fix spinlock race in kernel thread creation Context switching does take care to retain the correct lock owner across the switch from 'prev' to 'next' tasks. This does rely on interrupts remaining disabled for the entire duration of the switch. This condition is guaranteed for normal process creation and context switching between already running processes, because both 'prev' and 'next' already have interrupts disabled in their saved copies of the status register. The situation is different for newly created kernel threads. The status register is set to PS_S in copy_thread(), which does leave the IPL at 0. Upon restoring the 'next' thread's status register in switch_to() aka resume(), interrupts then become enabled prematurely. resume() then returns via ret_from_kernel_thread() and schedule_tail() where run queue lock is released (see finish_task_switch() and finish_lock_switch()). A timer interrupt calling scheduler_tick() before the lock is released in finish_task_switch() will find the lock already taken, with the current task as lock owner. This causes a spinlock recursion warning as reported by Guenter Roeck. As far as I can ascertain, this race has been opened in commit 533e6903bea0 ("m68k: split ret_from_fork(), simplify kernel_thread()") but I haven't done a detailed study of kernel history so it may well predate that commit. Interrupts cannot be disabled in the saved status register copy for kernel threads (init will complain about interrupts disabled when finally starting user space). Disable interrupts temporarily when switching the tasks' register sets in resume(). Note that a simple oriw 0x700,%sr after restoring sr is not enough here - this leaves enough of a race for the 'spinlock recursion' warning to still be observed. Tested on ARAnyM and qemu (Quadra 800 emulation).
References
- ubuntu.com/security/CVE-2024-38613 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-38613 (opens in a new tab)
- git.kernel.org/linus/da89ce46f02470ef08f0f580755d14d547da59ed (opens in a new tab)
- git.kernel.org/stable/c/2a8d1d95302c7d52c6ac8fa5cb4a6948ae0d3a14 (opens in a new tab)
- git.kernel.org/stable/c/5213cc01d0464c011fdc09f318705603ed3a746b (opens in a new tab)
- git.kernel.org/stable/c/4eeffecc8e3cce25bb559502c2fd94a948bcde82 (opens in a new tab)
- git.kernel.org/stable/c/77b2b67a0f8bce260c53907e5749d61466d90c87 (opens in a new tab)
- git.kernel.org/stable/c/0d9ae1253535f6e85a016e09c25ecbe6f7f59ef0 (opens in a new tab)
- git.kernel.org/stable/c/f3baf0f4f92af32943ebf27b960e0552c6c082fd (opens in a new tab)
- git.kernel.org/stable/c/f1d4274a84c069be0f6098ab10c3443fc1f7134c (opens in a new tab)
- git.kernel.org/stable/c/95f00caf767b5968c2c51083957b38be4748a78a (opens in a new tab)
- git.kernel.org/stable/c/da89ce46f02470ef08f0f580755d14d547da59ed (opens in a new tab)
- ubuntu.com/security/notices/USN-6949-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6952-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6953-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6955-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6949-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6952-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6951-2 (opens in a new tab)