arm64: mm: Fix lockless walks with static and dynamic page-table folding
Lina reports random oopsen originating from the fast GUP code when
16K pages are used with 4-level page-tables, the fourth level being
folded at runtime due to lack of LPA2.
In this configuration, the generic implementation of
p4d_offset_lockless() will return a 'p4d_t *' corresponding to the
'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range().
This is normally fine, but when the fourth level of page-table is folded
at runtime, pud_offset_lockless() will offset from the address of the
'p4d_t' to calculate the address of the PUD in the same page-table page.
This results in a stray stack read when the 'p4d_t' has been allocated
on the stack and can send the walker into the weeds.
Fix the problem by providing our own definition of p4d_offset_lockless()
when CONFIG_PGTABLE_LEVELS <= 4 which returns the real page-table
pointer rather than the address of the local stack variable.
No advisories yet.
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Mon, 29 Sep 2025 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Metrics |
cvssV3_1
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cvssV3_1
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Thu, 12 Sep 2024 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-125 | |
| Metrics |
cvssV3_1
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cvssV3_1
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Wed, 11 Sep 2024 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Mon, 19 Aug 2024 19:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
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cvssV3_1
|
Sat, 17 Aug 2024 09:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: arm64: mm: Fix lockless walks with static and dynamic page-table folding Lina reports random oopsen originating from the fast GUP code when 16K pages are used with 4-level page-tables, the fourth level being folded at runtime due to lack of LPA2. In this configuration, the generic implementation of p4d_offset_lockless() will return a 'p4d_t *' corresponding to the 'pgd_t' allocated on the stack of the caller, gup_fast_pgd_range(). This is normally fine, but when the fourth level of page-table is folded at runtime, pud_offset_lockless() will offset from the address of the 'p4d_t' to calculate the address of the PUD in the same page-table page. This results in a stray stack read when the 'p4d_t' has been allocated on the stack and can send the walker into the weeds. Fix the problem by providing our own definition of p4d_offset_lockless() when CONFIG_PGTABLE_LEVELS <= 4 which returns the real page-table pointer rather than the address of the local stack variable. | |
| Title | arm64: mm: Fix lockless walks with static and dynamic page-table folding | |
| References |
|
Projects
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Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-05-04T09:26:08.429Z
Reserved: 2024-07-30T07:40:12.268Z
Link: CVE-2024-42293
Updated: 2024-09-11T12:42:23.664Z
Status : Analyzed
Published: 2024-08-17T09:15:09.867
Modified: 2025-09-29T15:19:10.967
Link: CVE-2024-42293
OpenCVE Enrichment
Updated: 2025-07-12T22:09:37Z