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.
Metrics
Affected Vendors & Products
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 |
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CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
Metrics |
cvssV3_1
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cvssV3_1
|
Thu, 12 Sep 2024 10:30:00 +0000
Type | Values Removed | Values Added |
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Weaknesses | CWE-125 | |
Metrics |
cvssV3_1
|
cvssV3_1
|
Wed, 11 Sep 2024 13:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
ssvc
|
Mon, 19 Aug 2024 19:15:00 +0000
Type | Values Removed | Values Added |
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References |
| |
Metrics |
threat_severity
|
cvssV3_1
|
Sat, 17 Aug 2024 09:15:00 +0000
Type | Values Removed | Values Added |
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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 |
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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


Updated: 2025-07-12T22:09:37Z