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

drm/pagemap: Prevent double migration of device pages

A device-private folio migrated to system memory by a CPU fault can
remain reachable through the raw-PFN eviction path until migration
finalization drops the source reference.

If eviction selects the same device-private folio during this window,
it can attempt to migrate the folio again. The second migration can leave
an uncharged folio on an LRU list, causing folio_lruvec_lock_irqsave() to
retry indefinitely and resulting in a soft lockup and RCU stall.

Mark successfully migrated device-private folios using a low bit of
their zone_device_data before migration finalization. Make both CPU-fault
and raw-PFN migration paths skip device-private folios carrying this
flag.

Mask the flag when retrieving the drm_pagemap_zdd pointer and preserve
it when a device-private folio is split. Keeping the state on the physical
folio also avoids depending on a virtual address that may change before a
fault occurs.

v2:
- Replace the retired-PFN XArray with an embedded bitmap. (Matthew Brost)
- Mark every base page covered by a migrated folio so retirement remains
valid if the folio is later split.

v3:
- Store the migrated state in a low bit of zone_device_data instead of
adding virtual-range and bitmap tracking to the ZDD. (Matthew Brost)
- Mask the flag when retrieving the ZDD and preserve it when splitting
a folio.
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/

v4:
- Advance by the folio size only for migration entries marked with
MIGRATE_PFN_COMPOUND. (Sashiko)

v5:
- Simplify ZDD flag updates and folio iteration. (Matthew Brost)
- Skip retired device-private folios in the CPU-fault path. (Matthew Brost)
- Preserve flag bits while taking a new ZDD reference for split folios.

v6:
- Restore MIGRATE_PFN_COMPOUND-aware stepping so non-compound migration
entries are processed one at a time. (Sashiko)
- Drop the pre-existing fixes already covered by Matthew Brost's series:
https://patchwork.freedesktop.org/series/171651/

The lockup was observed as:
[10109.860465] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [kworker/u65:5:6557]
[10109.860524] Tainted: [S]=CPU_OUT_OF_SPEC, [O]=OOT_MODULE
[10109.860524] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023
[10109.860525] Workqueue: xe_page_fault_work_queue xe_pagefault_queue_work [xe]
[10109.860644] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80
[10109.860655] Call Trace:
[10109.860655] <TASK>
[10109.860657] folio_lruvec_lock_irqsave+0x216/0x220
[10109.860661] ? __pfx_lru_add+0x10/0x10
[10109.860665] folio_batch_move_lru+0xc8/0x450
[10109.860670] ? lock_acquire+0xc4/0x2d0
[10109.860674] ? __folio_batch_add_and_move+0x60/0x2e0
[10109.860677] ? folio_migrate_mapping+0xa6/0x110
[10109.860679] ? folio_migrate_flags+0x13b/0x1b0
[10109.860681] ? __pfx_lru_add+0x10/0x10
[10109.860683] __folio_batch_add_and_move+0xe7/0x2e0
[10109.860685] ? dma_iova_try_alloc+0xb0/0x140
[10109.860689] folio_add_lru+0x64/0x80
[10109.860691] __migrate_device_finalize+0x12c/0x270
[10109.860695] migrate_device_finalize+0x10/0x20
[10109.860698] drm_pagemap_evict_to_ram+0x185/0x370 [drm_gpusvm_helper]
[10109.860704] ? drm_pagemap_evict_to_ram+0x96/0x370 [drm_gpusvm_helper]
[10109.860709] xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860819] ? xe_svm_bo_evict+0x15/0x20 [xe]
[10109.860921] xe_bo_move+0x107e/0x1570 [xe]
[10109.860992] ? xe_ttm_tt_create+0x168/0x340 [xe]
[10109.861059] ? __up_read+0x98/0x2b0
[10109.861061] ? lock_is_held_type+0xa3/0x130
[10109.861067] ttm_bo_handle_move_mem+0xe8/0x1e0 [ttm]
[10109.861075] ttm_bo_evict+0x141/0x1c0 [ttm]
[10109.861081] ttm_bo_evict_cb+0x9f/0x100 [ttm]
[10109.861086] ttm_lru_walk_for_evict+0x84/0x190 [ttm]
[10109.861091] ? xe_ttm_vram_mgr_new+0x258/0x3a0 [xe]
[10109.861198] ttm_bo_alloc_resource+0x219/0
---truncated---

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History

Fri, 25 Sep 2026 13:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-570
CWE-665
CWE-682

Fri, 25 Sep 2026 10:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: drm/pagemap: Prevent double migration of device pages A device-private folio migrated to system memory by a CPU fault can remain reachable through the raw-PFN eviction path until migration finalization drops the source reference. If eviction selects the same device-private folio during this window, it can attempt to migrate the folio again. The second migration can leave an uncharged folio on an LRU list, causing folio_lruvec_lock_irqsave() to retry indefinitely and resulting in a soft lockup and RCU stall. Mark successfully migrated device-private folios using a low bit of their zone_device_data before migration finalization. Make both CPU-fault and raw-PFN migration paths skip device-private folios carrying this flag. Mask the flag when retrieving the drm_pagemap_zdd pointer and preserve it when a device-private folio is split. Keeping the state on the physical folio also avoids depending on a virtual address that may change before a fault occurs. v2: - Replace the retired-PFN XArray with an embedded bitmap. (Matthew Brost) - Mark every base page covered by a migrated folio so retirement remains valid if the folio is later split. v3: - Store the migrated state in a low bit of zone_device_data instead of adding virtual-range and bitmap tracking to the ZDD. (Matthew Brost) - Mask the flag when retrieving the ZDD and preserve it when splitting a folio. - Drop the pre-existing fixes already covered by Matthew Brost's series: https://patchwork.freedesktop.org/series/171651/ v4: - Advance by the folio size only for migration entries marked with MIGRATE_PFN_COMPOUND. (Sashiko) v5: - Simplify ZDD flag updates and folio iteration. (Matthew Brost) - Skip retired device-private folios in the CPU-fault path. (Matthew Brost) - Preserve flag bits while taking a new ZDD reference for split folios. v6: - Restore MIGRATE_PFN_COMPOUND-aware stepping so non-compound migration entries are processed one at a time. (Sashiko) - Drop the pre-existing fixes already covered by Matthew Brost's series: https://patchwork.freedesktop.org/series/171651/ The lockup was observed as: [10109.860465] watchdog: BUG: soft lockup - CPU#9 stuck for 26s! [kworker/u65:5:6557] [10109.860524] Tainted: [S]=CPU_OUT_OF_SPEC, [O]=OOT_MODULE [10109.860524] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 0812 02/24/2023 [10109.860525] Workqueue: xe_page_fault_work_queue xe_pagefault_queue_work [xe] [10109.860644] RIP: 0010:_raw_spin_unlock_irqrestore+0x57/0x80 [10109.860655] Call Trace: [10109.860655] <TASK> [10109.860657] folio_lruvec_lock_irqsave+0x216/0x220 [10109.860661] ? __pfx_lru_add+0x10/0x10 [10109.860665] folio_batch_move_lru+0xc8/0x450 [10109.860670] ? lock_acquire+0xc4/0x2d0 [10109.860674] ? __folio_batch_add_and_move+0x60/0x2e0 [10109.860677] ? folio_migrate_mapping+0xa6/0x110 [10109.860679] ? folio_migrate_flags+0x13b/0x1b0 [10109.860681] ? __pfx_lru_add+0x10/0x10 [10109.860683] __folio_batch_add_and_move+0xe7/0x2e0 [10109.860685] ? dma_iova_try_alloc+0xb0/0x140 [10109.860689] folio_add_lru+0x64/0x80 [10109.860691] __migrate_device_finalize+0x12c/0x270 [10109.860695] migrate_device_finalize+0x10/0x20 [10109.860698] drm_pagemap_evict_to_ram+0x185/0x370 [drm_gpusvm_helper] [10109.860704] ? drm_pagemap_evict_to_ram+0x96/0x370 [drm_gpusvm_helper] [10109.860709] xe_svm_bo_evict+0x15/0x20 [xe] [10109.860819] ? xe_svm_bo_evict+0x15/0x20 [xe] [10109.860921] xe_bo_move+0x107e/0x1570 [xe] [10109.860992] ? xe_ttm_tt_create+0x168/0x340 [xe] [10109.861059] ? __up_read+0x98/0x2b0 [10109.861061] ? lock_is_held_type+0xa3/0x130 [10109.861067] ttm_bo_handle_move_mem+0xe8/0x1e0 [ttm] [10109.861075] ttm_bo_evict+0x141/0x1c0 [ttm] [10109.861081] ttm_bo_evict_cb+0x9f/0x100 [ttm] [10109.861086] ttm_lru_walk_for_evict+0x84/0x190 [ttm] [10109.861091] ? xe_ttm_vram_mgr_new+0x258/0x3a0 [xe] [10109.861198] ttm_bo_alloc_resource+0x219/0 ---truncated---
Title drm/pagemap: Prevent double migration of device pages
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-25T10:35:55.743Z

Reserved: 2026-09-25T10:25:14.316Z

Link: CVE-2026-98106

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:41.110

Modified: 2026-09-25T11:17:41.110

Link: CVE-2026-98106

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-25T12:45:17Z

Weaknesses