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CVE-2024-56547· NVD / CVE Program· CNA Linux

rcu/nocb: Fix missed RCU barrier on deoffloading

Noroxi assessment

Priority: Monitor (action score 18/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: Linux Linux 224b62028959858294789772d372dcb36cf5f820, 2996980e20b7a54a1869df15b3445374b850b155.

Low priority for now. Upgrade to Linux Linux 224b62028959858294789772d372dcb36cf5f820, 2996980e20b7a54a1869df15b3445374b850b155 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix missed RCU barrier on deoffloading Currently, running rcutorture test with torture_type=rcu fwd_progress=8 n_barrier_cbs=8 nocbs_nthreads=8 nocbs_toggle=100 onoff_interval=60 test_boost=2, will trigger the following warning: WARNING: CPU: 19 PID: 100 at kernel/rcu/tree_nocb.h:1061 rcu_nocb_rdp_deoffload+0x292/0x2a0 RIP: 0010:rcu_nocb_rdp_deoffload+0x292/0x2a0 Call Trace: <TASK> ? __warn+0x7e/0x120 ? rcu_nocb_rdp_deoffload+0x292/0x2a0 ? report_bug+0x18e/0x1a0 ? handle_bug+0x3d/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? rcu_nocb_rdp_deoffload+0x292/0x2a0 rcu_nocb_cpu_deoffload+0x70/0xa0 rcu_nocb_toggle+0x136/0x1c0 ? __pfx_rcu_nocb_toggle+0x10/0x10 kthread+0xd1/0x100 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2f/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> CPU0 CPU2 CPU3 //rcu_nocb_toggle //nocb_cb_wait //rcutorture // deoffload CPU1 // process CPU1's rdp rcu_barrier() rcu_segcblist_entrain() rcu_segcblist_add_len(1); // len == 2 // enqueue barrier // callback to CPU1's // rdp->cblist rcu_do_batch() // invoke CPU1's rdp->cblist // callback rcu_barrier_callback() rcu_barrier() mutex_lock(&rcu_state.barrier_mutex); // still see len == 2 // enqueue barrier callback // to CPU1's rdp->cblist rcu_segcblist_entrain() rcu_segcblist_add_len(1); // len == 3 // decrement len rcu_segcblist_add_len(-2); kthread_parkme() // CPU1's rdp->cblist len == 1 // Warn because there is // still a pending barrier // trigger warning WARN_ON_ONCE(rcu_segcblist_n_cbs(&rdp->cblist)); cpus_read_unlock(); // wait CPU1 to comes online and // invoke barrier callback on // CPU1 rdp's->cblist wait_for_completion(&rcu_state.barrier_completion); // deoffload CPU4 cpus_read_lock() rcu_barrier() mutex_lock(&rcu_state.barrier_mutex); // block on barrier_mutex // wait rcu_barrier() on // CPU3 to unlock barrier_mutex // but CPU3 unlock barrier_mutex // need to wait CPU1 comes online // when CPU1 going online will block on cpus_write_lock The above scenario will not only trigger a WARN_ON_ONCE(), but also trigger a deadlock. Thanks to nocb locking, a second racing rcu_barrier() on an offline CPU will either observe the decremented callback counter down to 0 and spare the callback enqueue, or rcuo will observe the new callback and keep rdp->nocb_cb_sleep to false. Therefore check rdp->nocb_cb_sleep before parking to make sure no further rcu_barrier() is waiting on the rdp.

MediumCVSS 4.7 · v3.1—No exploit Fix available
Published
Dec 27, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 10th percentile
CWE
—

Report tools

JSON

Action score

18

Monitor

Low priority for now.

CVSS
18 / 40 · 4.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.12 and later · before 6.12.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.12affected
    • 1fcb932c8b5ce86219d7dedcd63659351a43291c and later · before 224b62028959858294789772d372dcb36cf5f820affected · git
    • 1fcb932c8b5ce86219d7dedcd63659351a43291c and later · before 2996980e20b7a54a1869df15b3445374b850b155affected · git
    • before 6.12not affected · semver
    • 6.12.2 and later · up to and including 6.12.*not affected · semver
    • 6.13 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.12.3-16.12.3-1
Red Hat:enterprise_linux_eus:10.0kernelbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64kbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debugbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-debuginfobefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-develbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-devel-matchedbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-modulesbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-modules-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debug-modules-extrabefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-debuginfobefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-develbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-devel-matchedbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-modulesbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-modules-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-64k-modules-extrabefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-abi-stablelistsbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-debugbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-debug-corebefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-debug-debuginfobefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0
Red Hat:enterprise_linux_eus:10.0kernel-debug-develbefore 0:6.12.0-55.76.1.el10_00:6.12.0-55.76.1.el10_0

+68

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    85Now
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
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Published before and after this one in the same product

  • ← EarlierCVE-2024-56543Dec 27, 2024 · wifi: ath12k: Skip Rx TID cleanup for self peer
    22Monitor
  • ← EarlierCVE-2024-56546Dec 27, 2024 · drivers: soc: xilinx: add the missing kfree in xlnx_add_cb_for_suspend()
    22Monitor
  • Later →CVE-2024-56548Dec 27, 2024 · hfsplus: don't query the device logical block size multiple times
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux224b62028959858294789772d372dcb36cf5f820Vendor (CNA)
Linux Linux2996980e20b7a54a1869df15b3445374b850b155Vendor (CNA)
debian:linux6.12.3-1 · Debian:13Package registry (OSV)
red hat:kernel-64k-debug-debuginfo0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debug-devel0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debug-devel-matched0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-debuginfo0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-devel0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-64k-devel-matched0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-debuginfo0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-devel0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debug-devel-matched0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debuginfo0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debuginfo-common-aarch640:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)
red hat:kernel-debuginfo-common-ppc64le0:6.12.0-55.76.1.el10_0 · Red Hat:enterprise_linux_eus:10.0Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records