Upstream information

CVE-2026-98939 at MITRE

Description

In the Linux kernel, the following vulnerability has been resolved:

x86/mm: Drop unnecessary PMD page copy when freeing

On a box with a discrete GPU, lockdep reports a possible deadlock as
soon as kswapd shrinks the TTM page pool. The immediate cause is an
x86 commit that added an mmap_read_lock() to kernel page protection
munging code.

The huge vmap code holds the same lock over a GFP_KERNEL allocation,
which is a no-no now that reclaim can take it. That allocation is in a
page table *free* path and ends up being for dubious purposes[1].
Basically, it tries to avoid hardware setting Accessed=1 in page table
entries that are unreachable by the hardware, a non-issue.

Remove the PMD copy. Detach the original PMD page at the PUD, flush
the mid-level caches, and free the PTE tables straight from the
detached PMD page. With no allocation left, the locking issue is gone.

Lockdep splat/analysis:

WARNING: possible circular locking dependency detected
7.3.0-rc3-f6e7b42bf05b+ #183 Tainted: G U
------------------------------------------------------
kswapd0/269 is trying to acquire lock:
((init_mm).mmap_lock){++++}-{4:4}, at: change_page_attr_set_clr+0x29a/0x4a0
but task is already holding lock:
(pool_shrink_rwsem){.+.+}-{4:4}, at: ttm_pool_shrink+0xb2/0x330 [ttm]
Chain exists of:
(init_mm).mmap_lock --> fs_reclaim --> pool_shrink_rwsem

The cycle is built from three edges:

1) pool_shrink_rwsem -> (init_mm).mmap_lock

The TTM shrinker restores the caching attribute of every page it
frees, while holding pool_shrink_rwsem:

ttm_pool_shrink()
-> ttm_pool_dispose_list()
-> ttm_pool_free_page()
-> set_pages_wb()
-> change_page_attr_set_clr() [ init_mm mmap read lock ]

2) fs_reclaim -> pool_shrink_rwsem

The same shrinker, called from reclaim.

3) (init_mm).mmap_lock -> fs_reclaim

ioremap() installing a huge PUD mapping over an existing PMD table:

ioremap_page_range()
-> vmap_range_noflush()
-> vmap_try_huge_pud() [ init_mm mmap read lock ]
-> pud_free_pmd_page()
-> __get_free_page(GFP_KERNEL) [ enters reclaim ]

[ dhansen: Lots of changelog munging/trimming and merged comments from my
version of the fix. ]

SUSE information

Overall state of this security issue: New

This issue is currently rated as having not set severity.

Note from the SUSE Security Team on the kernel-default package

SUSE will no longer fix all CVEs in the Linux Kernel anymore, but declare some bug classes as won't fix. Please refer to TID 21496 for more details.

No SUSE Bugzilla entries cross referenced.

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Desktop 15 SP7 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 15 SP7 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 16.0 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 16.0 kernel-source Analysis
SUSE Linux Enterprise High Availability Extension 16.1 kernel-default Analysis
SUSE Linux Enterprise High Availability Extension 16.1 kernel-source Analysis
SUSE Linux Enterprise Micro 5.3 kernel-default Analysis
SUSE Linux Enterprise Micro 5.3 kernel-rt Analysis
SUSE Linux Enterprise Micro 5.3 kernel-source Analysis
SUSE Linux Enterprise Micro 5.3 kernel-source-rt Analysis
SUSE Linux Enterprise Micro 5.4 kernel-default Analysis
SUSE Linux Enterprise Micro 5.4 kernel-rt Analysis
SUSE Linux Enterprise Micro 5.4 kernel-source Analysis
SUSE Linux Enterprise Micro 5.4 kernel-source-rt Analysis
SUSE Linux Enterprise Micro 5.5 kernel-default Analysis
SUSE Linux Enterprise Micro 5.5 kernel-source Analysis
SUSE Linux Enterprise Micro 5.5 kernel-source-rt Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP7 kernel-source-rt Analysis
SUSE Linux Enterprise Server 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Server 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Server 16.0 kernel-default Analysis
SUSE Linux Enterprise Server 16.0 kernel-source Analysis
SUSE Linux Enterprise Server 16.1 kernel-default Analysis
SUSE Linux Enterprise Server 16.1 kernel-source Analysis
SUSE Linux Enterprise Server 16.2 kernel-source Analysis
SUSE Linux Enterprise Server for NVIDIA 16.1 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP7 kernel-source Analysis
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-default Analysis
SUSE Linux Enterprise Server for SAP applications 16.0 kernel-source Analysis
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-default Analysis
SUSE Linux Enterprise Server for SAP applications 16.1 kernel-source Analysis
SUSE Linux Enterprise Server for SAP applications 16.2 kernel-source Analysis
SUSE Linux Micro 6.0 kernel-default Analysis
SUSE Linux Micro 6.0 kernel-source Analysis
SUSE Linux Micro 6.0 kernel-source-rt Analysis
SUSE Linux Micro 6.1 kernel-default Analysis
SUSE Linux Micro 6.1 kernel-source Analysis
SUSE Linux Micro 6.1 kernel-source-rt Analysis
SUSE Linux Micro 6.2 kernel-default Analysis
SUSE Linux Micro 6.2 kernel-source Analysis
SUSE Linux Micro Extras 6.0 kernel-default Analysis
SUSE Linux Micro Extras 6.0 kernel-source Analysis
SUSE Linux Micro Extras 6.0 kernel-source-rt Analysis
SUSE Linux Micro Extras 6.1 kernel-default Analysis
SUSE Linux Micro Extras 6.1 kernel-source Analysis
SUSE Real Time Module 15 SP7 kernel-source-rt Analysis
openSUSE Leap 16.0 kernel-source Analysis
openSUSE Leap 16.1 kernel-source Analysis
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-default Analysis
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-source Analysis
SUSE Linux Enterprise Server 12 SP5 kernel-source Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP6 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP6-LTSS kernel-source Analysis
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-default Analysis
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-default Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-source Analysis
Products past their end of life and not receiving proactive updates anymore.
SUSE CaaS Platform 4.0 kernel-source Analysis
SUSE Enterprise Storage 6 kernel-source Analysis
SUSE Enterprise Storage 7 kernel-source Analysis
SUSE Enterprise Storage 7.1 kernel-source Analysis
SUSE Linux Enterprise Desktop 11 SP4 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP5 kernel-source Analysis
SUSE Linux Enterprise Desktop 15 SP6 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4 kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS kernel-source Analysis
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source Analysis
SUSE Linux Enterprise Micro 5.0 kernel-default Analysis
SUSE Linux Enterprise Micro 5.1 kernel-default Analysis
SUSE Linux Enterprise Micro 5.2 kernel-default Analysis
SUSE Linux Enterprise Micro 5.2 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Module for Basesystem 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Module for Development Tools 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP4 kernel-source Analysis
SUSE Linux Enterprise Real Time 15 SP4 kernel-source-rt Analysis
SUSE Linux Enterprise Real Time 15 SP5 kernel-source-rt Analysis
SUSE Linux Enterprise Server 11 SP4 kernel-source Analysis
SUSE Linux Enterprise Server 11 SP4-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3 kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3-BCL kernel-source Analysis
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-default Analysis
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP1 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP2 kernel-source Analysis
SUSE Linux Enterprise Server for SAP Applications 15 SP3 kernel-source Analysis
SUSE Manager Proxy 4.0 kernel-source Analysis
SUSE Manager Proxy 4.1 kernel-source Analysis
SUSE Manager Proxy 4.2 kernel-source Analysis
SUSE Manager Proxy 4.3 kernel-source Analysis
SUSE Manager Proxy LTS 4.3 kernel-source Analysis
SUSE Manager Retail Branch Server 4.0 kernel-source Analysis
SUSE Manager Retail Branch Server 4.1 kernel-source Analysis
SUSE Manager Retail Branch Server 4.2 kernel-source Analysis
SUSE Manager Retail Branch Server 4.3 kernel-source Analysis
SUSE Manager Retail Branch Server LTS 4.3 kernel-source Analysis
SUSE Manager Server 4.0 kernel-source Analysis
SUSE Manager Server 4.1 kernel-source Analysis
SUSE Manager Server 4.2 kernel-source Analysis
SUSE Manager Server 4.3 kernel-source Analysis
SUSE Manager Server LTS 4.3 kernel-source Analysis
SUSE Real Time Module 15 SP4 kernel-source-rt Analysis
SUSE Real Time Module 15 SP5 kernel-source-rt Analysis
openSUSE Leap 15.3 kernel-source Analysis
openSUSE Leap 15.4 kernel-source Analysis
openSUSE Leap 15.4 kernel-source-rt Analysis
openSUSE Leap 15.5 kernel-source Analysis
openSUSE Leap 15.5 kernel-source-rt Analysis
openSUSE Leap 15.6 kernel-source Analysis


SUSE Timeline for this CVE

CVE page created: Fri Oct 23 21:53:40 2026
CVE page last modified: Fri Oct 23 21:53:40 2026