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

lib: alloc_tag_module_unload must wait for pending kfree_rcu calls

Ben Greear reports following splat:
------------[ cut here ]------------
net/netfilter/nf_nat_core.c:1114 module nf_nat func:nf_nat_register_fn has 256 allocated at module unload
WARNING: CPU: 1 PID: 10421 at lib/alloc_tag.c:168 alloc_tag_module_unload+0x22b/0x3f0
Modules linked in: nf_nat(-) btrfs ufs qnx4 hfsplus hfs minix vfat msdos fat
...
Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020
RIP: 0010:alloc_tag_module_unload+0x22b/0x3f0
codetag_unload_module+0x19b/0x2a0
? codetag_load_module+0x80/0x80

nf_nat module exit calls kfree_rcu on those addresses, but the free
operation is likely still pending by the time alloc_tag checks for leaks.

Wait for outstanding kfree_rcu operations to complete before checking
resolves this warning.

Reproducer:
unshare -n iptables-nft -t nat -A PREROUTING -p tcp
grep nf_nat /proc/allocinfo # will list 4 allocations
rmmod nft_chain_nat
rmmod nf_nat # will WARN.

[akpm@linux-foundation.org: add comment]
Published: 2024-11-09
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-7276-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7277-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-7310-1 Linux kernel vulnerabilities
History

Fri, 26 Sep 2025 18:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-401
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:*

Tue, 15 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00042}

epss

{'score': 0.00046}


Thu, 13 Feb 2025 00:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-667

Fri, 22 Nov 2024 14:00:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Sat, 09 Nov 2024 10:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: lib: alloc_tag_module_unload must wait for pending kfree_rcu calls Ben Greear reports following splat: ------------[ cut here ]------------ net/netfilter/nf_nat_core.c:1114 module nf_nat func:nf_nat_register_fn has 256 allocated at module unload WARNING: CPU: 1 PID: 10421 at lib/alloc_tag.c:168 alloc_tag_module_unload+0x22b/0x3f0 Modules linked in: nf_nat(-) btrfs ufs qnx4 hfsplus hfs minix vfat msdos fat ... Hardware name: Default string Default string/SKYBAY, BIOS 5.12 08/04/2020 RIP: 0010:alloc_tag_module_unload+0x22b/0x3f0 codetag_unload_module+0x19b/0x2a0 ? codetag_load_module+0x80/0x80 nf_nat module exit calls kfree_rcu on those addresses, but the free operation is likely still pending by the time alloc_tag checks for leaks. Wait for outstanding kfree_rcu operations to complete before checking resolves this warning. Reproducer: unshare -n iptables-nft -t nat -A PREROUTING -p tcp grep nf_nat /proc/allocinfo # will list 4 allocations rmmod nft_chain_nat rmmod nf_nat # will WARN. [akpm@linux-foundation.org: add comment]
Title lib: alloc_tag_module_unload must wait for pending kfree_rcu calls
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T20:47:35.662Z

Reserved: 2024-10-21T19:36:19.971Z

Link: CVE-2024-50212

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2024-11-09T11:15:04.940

Modified: 2025-09-26T18:21:11.440

Link: CVE-2024-50212

cve-icon Redhat

Severity : Moderate

Publid Date: 2024-11-09T00:00:00Z

Links: CVE-2024-50212 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2025-07-13T21:06:39Z

Weaknesses