medium 4.7

CVE-2024-38601 json

ring-buffer: Fix a race between readers and resize checks

published 2024-06-19 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-37464

cvss: 4.7; 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 7%
public exploits: 0; none known

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

The reader code in rb_get_reader_page() swaps a new reader page into the ring buffer by doing cmpxchg on old->list.prev->next to point it to the new page. Following that, if the operation is successful, old->list.next->prev gets updated too. This means the underlying doubly-linked list is temporarily inconsistent, page->prev->next or page->next->prev might not be equal back to page for some page in the ring buffer.

The resize operation in ring_buffer_resize() can be invoked in parallel. It calls rb_check_pages() which can detect the described inconsistency and stop further tracing:

[ 190.271762] ------------[ cut here ]------------ [ 190.271771] WARNING: CPU: 1 PID: 6186 at kernel/trace/ring_buffer.c:1467 rb_check_pages.isra.0+0x6a/0xa0 [ 190.271789] Modules linked in: [...] [ 190.271991] Unloaded tainted modules: intel_uncore_frequency(E):1 skx_edac(E):1 [ 190.272002] CPU: 1 PID: 6186 Comm: cmd.sh Kdump: loaded Tainted: G E 6.9.0-rc6-default #5 158d3e1e6d0b091c34c3b96bfd99a1c58306d79f [ 190.272011] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552c-rebuilt.opensuse.org 04/01/2014 [ 190.272015] RIP: 0010:rb_check_pages.isra.0+0x6a/0xa0 [ 190.272023] Code: [...] [ 190.272028] RSP: 0018:ffff9c37463abb70 EFLAGS: 00010206 [ 190.272034] RAX: ffff8eba04b6cb80 RBX: 0000000000000007 RCX: ffff8eba01f13d80 [ 190.272038] RDX: ffff8eba01f130c0 RSI: ffff8eba04b6cd00 RDI: ffff8eba0004c700 [ 190.272042] RBP: ffff8eba0004c700 R08: 0000000000010002 R09: 0000000000000000 [ 190.272045] R10: 00000000ffff7f52 R11: ffff8eba7f600000 R12: ffff8eba0004c720 [ 190.272049] R13: ffff8eba00223a00 R14: 0000000000000008 R15: ffff8eba067a8000 [ 190.272053] FS: 00007f1bd64752c0(0000) GS:ffff8eba7f680000(0000) knlGS:0000000000000000 [ 190.272057] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 190.272061] CR2: 00007f1bd6662590 CR3: 000000010291e001 CR4: 0000000000370ef0 [ 190.272070] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 190.272073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 190.272077] Call Trace: [ 190.272098] <TASK> [ 190.272189] ring_buffer_resize+0x2ab/0x460 [ 190.272199] __tracing_resize_ring_buffer.part.0+0x23/0xa0 [ 190.272206] tracing_resize_ring_buffer+0x65/0x90 [ 190.272216] tracing_entries_write+0x74/0xc0 [ 190.272225] vfs_write+0xf5/0x420 [ 190.272248] ksys_write+0x67/0xe0 [ 190.272256] do_syscall_64+0x82/0x170 [ 190.272363] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 190.272373] RIP: 0033:0x7f1bd657d263 [ 190.272381] Code: [...] [ 190.272385] RSP: 002b:00007ffe72b643f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 190.272391] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1bd657d263 [ 190.272395] RDX: 0000000000000002 RSI: 0000555a6eb538e0 RDI: 0000000000000001 [ 190.272398] RBP: 0000555a6eb538e0 R08: 000000000000000a R09: 0000000000000000 [ 190.272401] R10: 0000555a6eb55190 R11: 0000000000000246 R12: 00007f1bd6662500 [ 190.272404] R13: 0000000000000002 R14: 00007f1bd6667c00 R15: 0000000000000002 [ 190.272412] </TASK> [ 190.272414] ---[ end trace 0000000000000000 ]---

Note that ring_buffer_resize() calls rb_check_pages() only if the parent trace_buffer has recording disabled. Recent commit d78ab792705c ("tracing: Stop current tracer when resizing buffer") causes that it is now always the case which makes it more likely to experience this issue.

The window to hit this race is nonetheless very small. To help reproducing it, one can add a delay loop in rb_get_reader_page():

ret = rb_head_page_replace(reader, cpu_buffer->reader_page); if (!ret) goto spin; for (unsigned i = 0; i < 1U << 26; i++) /* inserted delay loop */ __asm__ __volatile__ ("" : : : "memory"); rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;

.. ---truncated---

Patch / fix

fixed in 1 distros 5 links 9

Linux Linux 4.19.316, 5.4.278, 5.10.219, 5.15.161, 6.1.93, 6.6.33, 6.8.12, 6.9.3, 6.10

debian ubuntu red hat suse almalinux

linux Debian 12 6.1.94-1
linux Debian 14, Debian 13 6.8.12-1

debian advisories DEBIAN-CVE-2024-38601

linux Ubuntu 20.04 LTS 5.4.0-192.212
linux Ubuntu 22.04 LTS 5.15.0-121.131
linux Ubuntu 24.04 LTS 6.8.0-40.40
linux-aws Ubuntu 20.04 LTS 5.4.0-1130.140
linux-aws Ubuntu 22.04 LTS 5.15.0-1069.75
linux-aws Ubuntu 24.04 LTS 6.8.0-1013.14
linux-gcp Ubuntu 20.04 LTS 5.4.0-1134.143
linux-gcp Ubuntu 22.04 LTS 5.15.0-1068.76

ubuntu advisories UBUNTU-CVE-2024-38601

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 9 5.14.0-427.37.1.el9_4
rv RHEL 9 5.14.0-427.37.1.el9_4
perf RHEL 9 5.14.0-427.37.1.el9_4
rtla RHEL 9 5.14.0-427.37.1.el9_4
bpftool RHEL 9 7.3.0-427.37.1.el9_4
libperf RHEL 9 5.14.0-427.37.1.el9_4
kernel-rt RHEL 9 5.14.0-427.37.1.el9_4
kernel-64k RHEL 9 5.14.0-427.37.1.el9_4

red hat advisories RHSA-2024:6997

kernel-rt Linux Micro 6.0 6.4.0-9.1
kernel-source-rt Linux Micro 6.0 6.4.0-9.1
kernel-source Linux Micro 6.0 6.4.0-18.1
kernel-default Linux Micro 6.0 6.4.0-18.1
kernel-kvmsmall Linux Micro 6.0 6.4.0-18.1
kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
kernel-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1
kernel-syms-rt Real Time Module 15 SP6, openSUSE Leap 15.6 6.4.0-150600.10.5.1

suse advisories SUSE-SU-2025:20028-1 SUSE-SU-2025:20008-1 SUSE-SU-2024:2973-1 SUSE-SU-2024:2939-1 SUSE-SU-2024:2896-1 SUSE-SU-2024:2571-1

kernel AlmaLinux 9 5.14.0-427.37.1.el9_4
rv AlmaLinux 9 5.14.0-427.37.1.el9_4
perf AlmaLinux 9 5.14.0-427.37.1.el9_4
rtla AlmaLinux 9 5.14.0-427.37.1.el9_4
bpftool AlmaLinux 9 7.3.0-427.37.1.el9_4
libperf AlmaLinux 9 5.14.0-427.37.1.el9_4
kernel-rt AlmaLinux 9 5.14.0-427.37.1.el9_4
kernel-64k AlmaLinux 9 5.14.0-427.37.1.el9_4

almalinux advisories ALSA-2024:6997

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-2024-38601 updated 2026-11-07 cvss 4.1

kernel: ring-buffer: Fix a race between readers and resize checks

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 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more 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 5.14.0-427.37.1.el9_4, perf 5.14.0-427.37.1.el9_4, rtla 5.14.0-427.37.1.el9_4, kernel-devel-matched 5.14.0-427.37.1.el9_4, kernel-64k-devel-matched 5.14.0-427.37.1.el9_4, kernel-debug-devel-matched 5.14.0-427.37.1.el9_4, +6 more Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.37.1.el9_4, kernel 5.14.0-427.37.1.el9_4, kernel-64k 5.14.0-427.37.1.el9_4, kernel-core 5.14.0-427.37.1.el9_4, kernel-tools 5.14.0-427.37.1.el9_4, python3-perf 5.14.0-427.37.1.el9_4, +28 more Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.37.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.37.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.37.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.37.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.37.1.el9_4 Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.37.1.el9_4, kernel-rt-kvm 5.14.0-427.37.1.el9_4, kernel-rt-core 5.14.0-427.37.1.el9_4, kernel-rt-modules 5.14.0-427.37.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.37.1.el9_4, kernel-rt-debug-core 5.14.0-427.37.1.el9_4, +6 more Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.37.1.el9_4, kernel-rt-core 5.14.0-427.37.1.el9_4, kernel-rt-modules 5.14.0-427.37.1.el9_4, kernel-rt-debug-core 5.14.0-427.37.1.el9_4, kernel-rt-modules-core 5.14.0-427.37.1.el9_4, kernel-rt-debug-modules 5.14.0-427.37.1.el9_4, +4 more
fixed: vendor fix RHSA-2024:6997
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
not affected: vulnerable code not present

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-25-226-15 updated 2026-02-25 cvss 0.0

Siemens SINEC OS

Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 3.1 Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family < 3.1
affected: fixed in V3.1 support.industry.siemens.com
Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
not affected

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 (2024-09-10)

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	4.7	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Linux Linux

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2024-38601
NVD CVE-2024-38601

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.

Summary