Improper Locking Affecting kernel-rt-modules-core package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

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  • Snyk IDSNYK-RHEL9-KERNELRTMODULESCORE-9449487
  • published15 Mar 2025
  • disclosed12 Mar 2025

Introduced: 12 Mar 2025

NewCVE-2025-21851  (opens in a new tab)
CWE-667  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-rt-modules-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-modules-core package and not the kernel-rt-modules-core package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

bpf: Fix softlockup in arena_map_free on 64k page kernel

On an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y, arena_htab tests cause a segmentation fault and soft lockup. The same failure is not observed with 4k pages on aarch64.

It turns out arena_map_free() is calling apply_to_existing_page_range() with the address returned by bpf_arena_get_kern_vm_start(). If this address is not page-aligned the code ends up calling apply_to_pte_range() with that unaligned address causing soft lockup.

Fix it by round up GUARD_SZ to PAGE_SIZE << 1 so that the division by 2 in bpf_arena_get_kern_vm_start() returns a page-aligned value.

CVSS Base Scores

version 3.1