CVE-2025-40230 : Detail

CVE-2025-40230

0.02%V4
2025-12-04
15h31 +00:00
2026-05-11
21h45 +00:00
CVE.org
NVD
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Deskripsi CVE

mm: prevent poison consumption when splitting THP

In the Linux kernel, the following vulnerability has been resolved: mm: prevent poison consumption when splitting THP When performing memory error injection on a THP (Transparent Huge Page) mapped to userspace on an x86 server, the kernel panics with the following trace. The expected behavior is to terminate the affected process instead of panicking the kernel, as the x86 Machine Check code can recover from an in-userspace #MC. mce: [Hardware Error]: CPU 0: Machine Check Exception: f Bank 3: bd80000000070134 mce: [Hardware Error]: RIP 10: {memchr_inv+0x4c/0xf0} mce: [Hardware Error]: TSC afff7bbff88a ADDR 1d301b000 MISC 80 PPIN 1e741e77539027db mce: [Hardware Error]: PROCESSOR 0:d06d0 TIME 1758093249 SOCKET 0 APIC 0 microcode 80000320 mce: [Hardware Error]: Run the above through 'mcelog --ascii' mce: [Hardware Error]: Machine check: Data load in unrecoverable area of kernel Kernel panic - not syncing: Fatal local machine check The root cause of this panic is that handling a memory failure triggered by an in-userspace #MC necessitates splitting the THP. The splitting process employs a mechanism, implemented in try_to_map_unused_to_zeropage(), which reads the pages in the THP to identify zero-filled pages. However, reading the pages in the THP results in a second in-kernel #MC, occurring before the initial memory_failure() completes, ultimately leading to a kernel panic. See the kernel panic call trace on the two #MCs. First Machine Check occurs // [1] memory_failure() // [2] try_to_split_thp_page() split_huge_page() split_huge_page_to_list_to_order() __folio_split() // [3] remap_page() remove_migration_ptes() remove_migration_pte() try_to_map_unused_to_zeropage() // [4] memchr_inv() // [5] Second Machine Check occurs // [6] Kernel panic [1] Triggered by accessing a hardware-poisoned THP in userspace, which is typically recoverable by terminating the affected process. [2] Call folio_set_has_hwpoisoned() before try_to_split_thp_page(). [3] Pass the RMP_USE_SHARED_ZEROPAGE remap flag to remap_page(). [4] Try to map the unused THP to zeropage. [5] Re-access pages in the hw-poisoned THP in the kernel. [6] Triggered in-kernel, leading to a panic kernel. In Step[2], memory_failure() sets the poisoned flag on the page in the THP by TestSetPageHWPoison() before calling try_to_split_thp_page(). As suggested by David Hildenbrand, fix this panic by not accessing to the poisoned page in the THP during zeropage identification, while continuing to scan unaffected pages in the THP for possible zeropage mapping. This prevents a second in-kernel #MC that would cause kernel panic in Step[4]. Thanks to Andrew Zaborowski for his initial work on fixing this issue.

Informasi CVE

EPSS

EPSS adalah model penilaian yang memprediksi kemungkinan suatu kerentanan dieksploitasi.

Skor EPSS

Model EPSS menghasilkan skor probabilitas antara 0 dan 1 (0 hingga 100%). Semakin tinggi skor, semakin besar probabilitas bahwa suatu kerentanan akan dieksploitasi.

Persentil EPSS

Persentil digunakan untuk meranking CVE berdasarkan skor EPSS mereka. Misalnya, CVE di persentil ke-95 berdasarkan skor EPSS-nya lebih mungkin dieksploitasi daripada 95% CVE lainnya. Dengan demikian, persentil digunakan untuk membandingkan skor EPSS suatu CVE dengan CVE lainnya.
EPSS First.org

Referensi

Informasi yang disajikan di CVE Find berasal dari beberapa sumber referensi yang dipilih dengan cermat. Data CVE disediakan oleh MITRE Corporation dan National Vulnerability Database (NVD). Katalog Known Exploited Vulnerabilities (KEV) bersumber dari Cybersecurity and Infrastructure Security Agency (CISA), sementara skor EPSS berasal dari FIRST.org. Selain itu, data mengenai kelemahan perangkat lunak (CWE) dan pola serangan umum (CAPEC) dikelola oleh MITRE Corporation, dan informasi tentang konfigurasi perangkat keras dan perangkat lunak (CPE) disediakan oleh NVD.