{"id":"CVE-2025-21851","summary":"bpf: Fix softlockup in arena_map_free on 64k page kernel","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix softlockup in arena_map_free on 64k page kernel\n\nOn an aarch64 kernel with CONFIG_PAGE_SIZE_64KB=y,\narena_htab tests cause a segmentation fault and soft lockup.\nThe same failure is not observed with 4k pages on aarch64.\n\nIt turns out arena_map_free() is calling\napply_to_existing_page_range() with the address returned by\nbpf_arena_get_kern_vm_start().  If this address is not page-aligned\nthe code ends up calling apply_to_pte_range() with that unaligned\naddress causing soft lockup.\n\nFix it by round up GUARD_SZ to PAGE_SIZE \u003c\u003c 1 so that the\ndivision by 2 in bpf_arena_get_kern_vm_start() returns\na page-aligned value.","modified":"2026-03-12T19:03:58.802442Z","published":"2025-03-12T09:42:06.480Z","related":["ALSA-2025:20095","ALSA-2025:20518","USN-7521-2"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21851.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/517e8a7835e8cfb398a0aeb0133de50e31cae32b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/787d556a3de447e70964a4bdeba9196f62a62b1e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c1f3f3892d4526f18aaeffdb6068ce861e793ee3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21851.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-21851"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"317460317a02a1af512697e6e964298dedd8a163"},{"fixed":"c1f3f3892d4526f18aaeffdb6068ce861e793ee3"},{"fixed":"787d556a3de447e70964a4bdeba9196f62a62b1e"},{"fixed":"517e8a7835e8cfb398a0aeb0133de50e31cae32b"}]}],"versions":["v6.10","v6.10-rc1","v6.10-rc2","v6.10-rc3","v6.10-rc4","v6.10-rc5","v6.10-rc6","v6.10-rc7","v6.11","v6.11-rc1","v6.11-rc2","v6.11-rc3","v6.11-rc4","v6.11-rc5","v6.11-rc6","v6.11-rc7","v6.12","v6.12-rc1","v6.12-rc2","v6.12-rc3","v6.12-rc4","v6.12-rc5","v6.12-rc6","v6.12-rc7","v6.12.1","v6.12.10","v6.12.11","v6.12.12","v6.12.13","v6.12.14","v6.12.15","v6.12.16","v6.12.2","v6.12.3","v6.12.4","v6.12.5","v6.12.6","v6.12.7","v6.12.8","v6.12.9","v6.13","v6.13-rc1","v6.13-rc2","v6.13-rc3","v6.13-rc4","v6.13-rc5","v6.13-rc6","v6.13-rc7","v6.13.1","v6.13.2","v6.13.3","v6.13.4","v6.8","v6.8-rc7","v6.9","v6.9-rc1","v6.9-rc2","v6.9-rc3","v6.9-rc4","v6.9-rc5","v6.9-rc6","v6.9-rc7"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21851.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"}]}