fs/proc/task_mmu: fix loss of young/dirty bits during pagemap scan
make_uffd_wp_pte() was previously doing:
pte = ptep_get(ptep);
ptep_modify_prot_start(ptep);
pte = pte_mkuffd_wp(pte);
ptep_modify_prot_commit(ptep, pte);
But if another thread accessed or dirtied the pte between the first 2
calls, this could lead to loss of that information. Since
ptep_modify_prot_start() gets and clears atomically, the following is the
correct pattern and prevents any possible race. Any access after the
first call would see an invalid pte and cause a fault:
pte = ptep_modify_prot_start(ptep);
pte = pte_mkuffd_wp(pte);
ptep_modify_prot_commit(ptep, pte);
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
| Source | ID | Title |
|---|---|---|
Ubuntu USN |
USN-6949-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6949-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6952-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-6955-1 | Linux kernel (OEM) vulnerabilities |
Wed, 01 Oct 2025 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.9:rc7:*:*:*:*:*:* |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T20:17:29.532Z
Reserved: 2024-05-30T15:25:07.073Z
Link: CVE-2024-36943
Updated: 2024-08-02T03:43:50.375Z
Status : Analyzed
Published: 2024-05-30T16:15:17.307
Modified: 2025-10-01T14:01:41.420
Link: CVE-2024-36943
OpenCVE Enrichment
Updated: 2025-07-12T22:31:27Z
Ubuntu USN