FKIE_CVE-2026-53108

Vulnerability from fkie_nvd - Published: 2026-06-24 17:17 - Updated: 2026-06-24 17:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: powerpc/64s: Fix unmap race with PMD migration entries The following race is possible with migration swap entries or device-private THP entries. e.g. when move_pages is called on a PMD THP page, then there maybe an intermediate state, where PMD entry acts as a migration swap entry (pmd_present() is true). Then if an munmap happens at the same time, then this VM_BUG_ON() can happen in pmdp_huge_get_and_clear_full(). This patch fixes that. Thread A: move_pages() syscall add_folio_for_migration() mmap_read_lock(mm) folio_isolate_lru(folio) mmap_read_unlock(mm) do_move_pages_to_node() migrate_pages() try_to_migrate_one() spin_lock(ptl) set_pmd_migration_entry() pmdp_invalidate() # PMD: _PAGE_INVALID | _PAGE_PTE | pfn set_pmd_at() # PMD: migration swap entry (pmd_present=0) spin_unlock(ptl) [page copy phase] # <--- RACE WINDOW --> Thread B: munmap() mmap_write_downgrade(mm) unmap_vmas() -> zap_pmd_range() zap_huge_pmd() __pmd_trans_huge_lock() pmd_is_huge(): # !pmd_present && !pmd_none -> TRUE (swap entry) pmd_lock() -> # spin_lock(ptl), waits for Thread A to release ptl pmdp_huge_get_and_clear_full() VM_BUG_ON(!pmd_present(*pmdp)) # HITS! [ 287.738700][ T1867] ------------[ cut here ]------------ [ 287.743843][ T1867] kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:187! cpu 0x0: Vector: 700 (Program Check) at [c00000044037f4f0] pc: c000000000094ca4: pmdp_huge_get_and_clear_full+0x6c/0x23c lr: c000000000645dec: zap_huge_pmd+0xb0/0x868 sp: c00000044037f790 msr: 800000000282b033 current = 0xc0000004032c1a00 paca = 0xc000000004fe0000 irqmask: 0x03 irq_happened: 0x09 pid = 1867, comm = a.out kernel BUG at :187! Linux version 6.19.0-12136-g14360d4f917c-dirty (powerpc64le-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #27 SMP PREEMPT Sun Feb 22 10:38:56 IST 2026 enter ? for help [link register ] c000000000645dec zap_huge_pmd+0xb0/0x868 [c00000044037f790] c00000044037f7d0 (unreliable) [c00000044037f7d0] c000000000645dcc zap_huge_pmd+0x90/0x868 [c00000044037f840] c0000000005724cc unmap_page_range+0x176c/0x1f40 [c00000044037fa00] c000000000572ea0 unmap_vmas+0xb0/0x1d8 [c00000044037fa90] c0000000005af254 unmap_region+0xb4/0x128 [c00000044037fb50] c0000000005af400 vms_complete_munmap_vmas+0x138/0x310 [c00000044037fbe0] c0000000005b0f1c do_vmi_align_munmap+0x1ec/0x238 [c00000044037fd30] c0000000005b3688 __vm_munmap+0x170/0x1f8 [c00000044037fdf0] c000000000587f74 sys_munmap+0x2c/0x40 [c00000044037fe10] c000000000032668 system_call_exception+0x128/0x350 [c00000044037fe50] c00000000000d05c system_call_vectored_common+0x15c/0x2ec ---- Exception: 3000 (System Call Vectored) at 0000000010064a2c SP (7fff9b1ee9c0) is in userspace 0:mon> zh commit a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages"), enabled migration for device-private PMD entries. Hence this is one other path where this warning could get trigger from. ------------[ cut here ]------------ WARNING: arch/powerpc/mm/book3s64/hash_pgtable.c:199 at hash__pmd_hugepage_update+0x48/0x284, CPU#3: hmm-tests/1905 Modules linked in: test_hmm CPU: 3 UID: 0 PID: 1905 Comm: hmm-tests Tainted: G B W L N 7.0.0-rc1-01438-g7e2f0ee7581c #21 PREEMPT Tainted: [B]=BAD_PAGE, [W]=WARN, [L]=SOFTLOCKUP, [N]=TEST Hardware name: IBM pSeries (emulated by qemu) POWER10 (architected) 0x801200 0xf000006 of:SLOF,git-ee03ae pSeries NIP [c000000000096b70] hash__pmd_hugepage_update+0x48/0x284 LR [c000000000096e7c] hash__pmdp_huge_get_and_clear+0xd0/0xd4 Call Trace: [c000000604707670] [c000000004e102b8] 0xc000000004e102b8 (unreliable) [c000000604707700] [c00000000064ec3c] set_pmd_migration_entry+0x414/0x498 [c000000604707760] [c00000000063e5a4] migrate_vma_col ---truncated---
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/829367e55012c053738ebe7db20c4a90d6609ece
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bbcbf045d6c778e82b47a35fc8728387708e9a3d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/book3s/64/pgtable.h",
            "arch/powerpc/mm/book3s64/pgtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "829367e55012c053738ebe7db20c4a90d6609ece",
              "status": "affected",
              "version": "75358ea359e7c0dfceb3c7b3d854570b4260cb7f",
              "versionType": "git"
            },
            {
              "lessThan": "bbcbf045d6c778e82b47a35fc8728387708e9a3d",
              "status": "affected",
              "version": "75358ea359e7c0dfceb3c7b3d854570b4260cb7f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/powerpc/include/asm/book3s/64/pgtable.h",
            "arch/powerpc/mm/book3s64/pgtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/64s: Fix unmap race with PMD migration entries\n\nThe following race is possible with migration swap entries or\ndevice-private THP entries. e.g. when move_pages is called on a PMD THP\npage, then there maybe an intermediate state, where PMD entry acts as\na migration swap entry (pmd_present() is true). Then if an munmap\nhappens at the same time, then this VM_BUG_ON() can happen in\npmdp_huge_get_and_clear_full().\n\nThis patch fixes that.\n\nThread A: move_pages() syscall\n  add_folio_for_migration()\n    mmap_read_lock(mm)\n    folio_isolate_lru(folio)\n    mmap_read_unlock(mm)\n\n  do_move_pages_to_node()\n    migrate_pages()\n      try_to_migrate_one()\n        spin_lock(ptl)\n        set_pmd_migration_entry()\n          pmdp_invalidate()     # PMD: _PAGE_INVALID | _PAGE_PTE | pfn\n          set_pmd_at()          # PMD: migration swap entry (pmd_present=0)\n        spin_unlock(ptl)\n        [page copy phase]       # \u003c--- RACE WINDOW --\u003e\n\nThread B: munmap()\n  mmap_write_downgrade(mm)\n  unmap_vmas() -\u003e zap_pmd_range()\n    zap_huge_pmd()\n      __pmd_trans_huge_lock()\n        pmd_is_huge():          # !pmd_present \u0026\u0026 !pmd_none -\u003e TRUE (swap entry)\n        pmd_lock() -\u003e \t\t# spin_lock(ptl), waits for Thread A to release ptl\n      pmdp_huge_get_and_clear_full()\n        VM_BUG_ON(!pmd_present(*pmdp))  # HITS!\n\n[  287.738700][ T1867] ------------[ cut here ]------------\n[  287.743843][ T1867] kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:187!\ncpu 0x0: Vector: 700 (Program Check) at [c00000044037f4f0]\n    pc: c000000000094ca4: pmdp_huge_get_and_clear_full+0x6c/0x23c\n    lr: c000000000645dec: zap_huge_pmd+0xb0/0x868\n    sp: c00000044037f790\n   msr: 800000000282b033\n  current = 0xc0000004032c1a00\n  paca    = 0xc000000004fe0000   irqmask: 0x03   irq_happened: 0x09\n    pid   = 1867, comm = a.out\nkernel BUG at :187!\nLinux version 6.19.0-12136-g14360d4f917c-dirty (powerpc64le-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #27 SMP PREEMPT Sun Feb 22 10:38:56 IST 2026\nenter ? for help\n[link register   ] c000000000645dec zap_huge_pmd+0xb0/0x868\n[c00000044037f790] c00000044037f7d0 (unreliable)\n[c00000044037f7d0] c000000000645dcc zap_huge_pmd+0x90/0x868\n[c00000044037f840] c0000000005724cc unmap_page_range+0x176c/0x1f40\n[c00000044037fa00] c000000000572ea0 unmap_vmas+0xb0/0x1d8\n[c00000044037fa90] c0000000005af254 unmap_region+0xb4/0x128\n[c00000044037fb50] c0000000005af400 vms_complete_munmap_vmas+0x138/0x310\n[c00000044037fbe0] c0000000005b0f1c do_vmi_align_munmap+0x1ec/0x238\n[c00000044037fd30] c0000000005b3688 __vm_munmap+0x170/0x1f8\n[c00000044037fdf0] c000000000587f74 sys_munmap+0x2c/0x40\n[c00000044037fe10] c000000000032668 system_call_exception+0x128/0x350\n[c00000044037fe50] c00000000000d05c system_call_vectored_common+0x15c/0x2ec\n---- Exception: 3000 (System Call Vectored) at 0000000010064a2c\nSP (7fff9b1ee9c0) is in userspace\n0:mon\u003e zh\n\ncommit a30b48bf1b24 (\"mm/migrate_device: implement THP migration of zone device pages\"),\nenabled migration for device-private PMD entries. Hence this is one\nother path where this warning could get trigger from.\n\n ------------[ cut here ]------------\n WARNING: arch/powerpc/mm/book3s64/hash_pgtable.c:199 at hash__pmd_hugepage_update+0x48/0x284, CPU#3: hmm-tests/1905\n Modules linked in: test_hmm\n CPU: 3 UID: 0 PID: 1905 Comm: hmm-tests Tainted: G    B   W    L   N  7.0.0-rc1-01438-g7e2f0ee7581c #21 PREEMPT\n Tainted: [B]=BAD_PAGE, [W]=WARN, [L]=SOFTLOCKUP, [N]=TEST\n Hardware name: IBM pSeries (emulated by qemu) POWER10 (architected) 0x801200 0xf000006 of:SLOF,git-ee03ae pSeries\n NIP [c000000000096b70] hash__pmd_hugepage_update+0x48/0x284\n LR [c000000000096e7c] hash__pmdp_huge_get_and_clear+0xd0/0xd4\n Call Trace:\n [c000000604707670] [c000000004e102b8] 0xc000000004e102b8 (unreliable)\n [c000000604707700] [c00000000064ec3c] set_pmd_migration_entry+0x414/0x498\n [c000000604707760] [c00000000063e5a4] migrate_vma_col\n---truncated---"
    }
  ],
  "id": "CVE-2026-53108",
  "lastModified": "2026-06-24T17:17:25.107",
  "metrics": {},
  "published": "2026-06-24T17:17:25.107",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/829367e55012c053738ebe7db20c4a90d6609ece"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bbcbf045d6c778e82b47a35fc8728387708e9a3d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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