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Improper Locking The advisory has been revoked - it doesn't affect any version of package kernel-64k-devel-matched  (opens in a new tab)

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  • Snyk IDSNYK-ALMALINUX10-KERNEL64KDEVELMATCHED-14120551
  • published26 Nov 2025
  • disclosed11 Nov 2025
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Introduced: 11 Nov 2025

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

Amendment

The AlmaLinux security team deemed this advisory irrelevant for AlmaLinux:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-devel-matched package and not the kernel-64k-devel-matched package as distributed by AlmaLinux.

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.