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Unrated severityNVD Advisory· Published Mar 12, 2025· Updated Oct 1, 2025

bpf: Fix softlockup in arena_map_free on 64k page kernel

CVE-2025-21851

Description

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.

Affected products

78

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

3

News mentions

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