LiveActive security incident?Get immediate response
CVE Record

CVE-2023-53859: s390/idle: mark arch_cpu_idle() noinstr

In the Linux kernel, the following vulnerability has been resolved: s390/idle: mark arch_cpu_idle() noinstr linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()") adds a new warning which hits on s390's arch_cpu_idle() function: RCU not on for: arch_cpu_idle+0x0/0x28 WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258 Modules linked in: CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4 Hardware name: IBM 8561 T01 703 (z/VM 7.3.0) Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3 Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000 0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000 0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0 0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8 Krnl Code: 00000000002b55b0: c02000840051 larl %r2,0000000001335652 00000000002b55b6: c0e5fff512d1 brasl %r14,0000000000157b58 #00000000002b55bc: af000000 mc 0,0 >00000000002b55c0: a7f4ffe7 brc 15,00000000002b558e 00000000002b55c4: 0707 bcr 0,%r7 00000000002b55c6: 0707 bcr 0,%r7 00000000002b55c8: eb6ff0480024 stmg %r6,%r15,72(%r15) 00000000002b55ce: b90400ef lgr %r14,%r15 Call Trace: [<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258 ([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258) [<0000000000f5f0fc>] ftrace_common+0x1c/0x20 [<00000000001044f6>] arch_cpu_idle+0x6/0x28 [<0000000000f4acf6>] default_idle_call+0x76/0x128 [<00000000001cc374>] do_idle+0xf4/0x1b0 [<00000000001cc6ce>] cpu_startup_entry+0x36/0x40 [<0000000000119d00>] smp_start_secondary+0x140/0x150 [<0000000000f5d2ae>] restart_int_handler+0x6e/0x90 Mark arch_cpu_idle() noinstr like all other architectures with CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE is a Linux kernel issue in the s390 idle path. The public record describes a kernel warning when tracing reaches arch_cpu_idle() while RCU is not watching. It does not describe data theft, privilege escalation, remote code execution, or service compromise.

Executive priority

Treat this as a targeted kernel maintenance item, not an emergency, unless critical s390 workloads depend on affected kernels. No active exploitation is documented in the provided sources.

Technical view

The fix marks s390 arch_cpu_idle() as noinstr, aligning it with other CONFIG_ARCH_WANTS_NO_INSTR architectures. The described failure is an RCU/tracing warning in the idle path after a linux-next tracing warning change. Stable kernel commits are listed as references.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds on the s390 architecture. The source lists Linux kernel affected version data but provides no CPEs or vendor-specific distribution mapping.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation or public weaponization. The available description is diagnostic and patch-oriented, not an exploitation narrative.

Researcher notes

Evidence is incomplete for security impact: no CVSS, CWE, exploit status, or concrete attacker outcome is provided. The strongest facts are the affected Linux kernel context, s390-specific idle path, warning trace, and referenced stable commits.

Mitigation direction

  • Identify Linux systems running s390 kernels in the affected version ranges.
  • Review vendor or distribution kernel advisories for packaged fixed versions.
  • Prioritize kernel updates where s390 production workloads are in scope.
  • If patching is delayed, monitor for kernel warnings related to arch_cpu_idle and RCU.

Validation and detection

  • Inventory kernel versions and architecture across Linux fleets.
  • Confirm whether running kernels include one of the referenced stable fixes.
  • Check distribution changelogs for CVE-2023-53859 or the s390 idle noinstr patch.
  • Review kernel logs for matching RCU/tracing warnings on s390 hosts.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2023-53859 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux1098582a0f6c4e8fd28da0a6305f9233d02c9c1d, 1098582a0f6c4e8fd28da0a6305f9233d02c9c1d, 1098582a0f6c4e8fd28da0a6305f9233d02c9c1d, 1098582a0f6c4e8fd28da0a6305f9233d02c9c1d, 788621afda4101ca0fae48de424040cda78193fe, 4.19.297unaffected
LinuxLinux5.9, 0, 5.15.99, 6.1.16, 6.2.3, 6.3affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.