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Fencer Vulns
medium 5.5

CVE-2024-42096 json

x86: stop playing stack games in profile_pc()

published 2024-07-29 2 y ago modified 2026-10-15 25 d ago also EUVD-2024-39928

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

x86: stop playing stack games in profile_pc()

The 'profile_pc()' function is used for timer-based profiling, which isn't really all that relevant any more to begin with, but it also ends up making assumptions based on the stack layout that aren't necessarily valid.

Basically, the code tries to account the time spent in spinlocks to the caller rather than the spinlock, and while I support that as a concept, it's not worth the code complexity or the KASAN warnings when no serious profiling is done using timers anyway these days.

And the code really does depend on stack layout that is only true in the simplest of cases. We've lost the comment at some point (I think when the 32-bit and 64-bit code was unified), but it used to say:

Assume the lock function has either no stack frame or a copy of eflags from PUSHF.

which explains why it just blindly loads a word or two straight off the stack pointer and then takes a minimal look at the values to just check if they might be eflags or the return pc:

Eflags always has bits 22 and up cleared unlike kernel addresses

but that basic stack layout assumption assumes that there isn't any lock debugging etc going on that would complicate the code and cause a stack frame.

It causes KASAN unhappiness reported for years by syzkaller [1] and others [2].

With no real practical reason for this any more, just remove the code.

Just for historical interest, here's some background commits relating to this code from 2006:

0cb91a229364 ("i386: Account spinlocks to the caller during profiling for !FP kernels") 31679f38d886 ("Simplify profile_pc on x86-64")

and a code unification from 2009:

ef4512882dbe ("x86: time_32/64.c unify profile_pc")

but the basics of this thing actually goes back to before the git tree.

Patch / fix

  • Linux Linux 4.19.317, 5.4.279, 5.10.221, 5.15.162, 6.1.97, 6.6.37, 6.9.8, 6.10
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • linux Debian 12 6.1.98-1
  • linux Debian 14, Debian 13 6.9.8-1

debian advisories DEBIAN-CVE-2024-42096

  • linux Ubuntu 20.04 LTS 5.4.0-195.215
  • linux Ubuntu 22.04 LTS 5.15.0-121.131
  • linux Ubuntu 24.04 LTS 6.8.0-48.48
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1132.142
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1069.75
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1018.20
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1136.145
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1068.76

ubuntu advisories UBUNTU-CVE-2024-42096

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 8 4.18.0-553.22.1.el8_10
  • perf RHEL 8 4.18.0-553.22.1.el8_10
  • bpftool RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.22.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.22.1.el8_10

red hat advisories RHSA-2024:7000RHSA-2024:7001RHSA-2024:6567

  • kernel-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-livepatch-MICRO-6-0-RT_Update_2 Linux Micro 6.0 1-1.1
  • kernel-source Linux Micro 6.0 6.4.0-19.1
  • kernel-default Linux Micro 6.0 6.4.0-19.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-19.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-livepatch-MICRO-6-0_Update_2 Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20047-1SUSE-SU-2025:20044-1SUSE-SU-2024:3383-1SUSE-SU-2024:3195-1SUSE-SU-2024:3194-1SUSE-SU-2024:2947-1

  • kernel AlmaLinux 8 4.18.0-553.22.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.22.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.22.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.22.1.el8_10

almalinux advisories ALSA-2024:7000ALSA-2024:7001ALSA-2024:6567

  • kernel Rocky Linux 8 4.18.0-553.22.1.el8_10
  • kernel-rt Rocky Linux 8 4.18.0-553.22.1.rt7.363.el8_10
  • kernel Rocky Linux 9 5.14.0-427.35.1.el9_4.cloud.1.0
  • kernel Rocky Linux 9 5.14.0-427.35.1.el9_4

rocky linux advisories RLSA-2024:7000RLSA-2024:7001RXSA-2024:6567RLSA-2024:6567

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-42096 updated cvss 5.1

kernel: x86: stop playing stack games in profile_pc()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.35.1.el9_4, perf 5.14.0-427.35.1.el9_4, rtla 5.14.0-427.35.1.el9_4, kernel-devel-matched 5.14.0-427.35.1.el9_4, kernel-64k-devel-matched 5.14.0-427.35.1.el9_4, kernel-debug-devel-matched 5.14.0-427.35.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:6567
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.22.1.el8_10, kernel 4.18.0-553.22.1.el8_10, bpftool 4.18.0-553.22.1.el8_10, kernel-core 4.18.0-553.22.1.el8_10, kernel-tools 4.18.0-553.22.1.el8_10, python3-perf 4.18.0-553.22.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:7000
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.35.1.el9_4, kernel 5.14.0-427.35.1.el9_4, kernel-64k 5.14.0-427.35.1.el9_4, kernel-core 5.14.0-427.35.1.el9_4, kernel-tools 5.14.0-427.35.1.el9_4, python3-perf 5.14.0-427.35.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:6567
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.22.1.el8_10
    fixed: vendor fix RHSA-2024:7000
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.35.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.35.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.35.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.35.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.35.1.el9_4
    fixed: vendor fix RHSA-2024:6567
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, +4 more
    fixed: vendor fix RHSA-2024:7001
show 4 more
  • Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.35.1.el9_4, kernel-rt-kvm 5.14.0-427.35.1.el9_4, kernel-rt-core 5.14.0-427.35.1.el9_4, kernel-rt-modules 5.14.0-427.35.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.35.1.el9_4, kernel-rt-debug-core 5.14.0-427.35.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:6567
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules-extra 4.18.0-553.22.1.rt7.363.el8_10, +2 more
    fixed: vendor fix RHSA-2024:7001
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.35.1.el9_4, kernel-rt-core 5.14.0-427.35.1.el9_4, kernel-rt-modules 5.14.0-427.35.1.el9_4, kernel-rt-debug-core 5.14.0-427.35.1.el9_4, kernel-rt-modules-core 5.14.0-427.35.1.el9_4, kernel-rt-debug-modules 5.14.0-427.35.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:6567
  • Red Hat OpenShift AI 8 rhoai/odh-rhel8-operator v2.13.1-2, rhoai/odh-dashboard-rhel8 v2.13.1-1, rhoai/odh-modelmesh-rhel8 v2.13.1-1, rhoai/odh-operator-bundle v2.13.1-2, rhoai/odh-rhel8-operator v2.14.0-24, rhoai/odh-dashboard-rhel8 v2.14.0-11, +56 more
    fixed: vendor fix RHBA-2024:8413

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-24-102-01 updated cvss 5.1

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-23-348-10 updated cvss 5.1

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.