fs/proc/task_mmu: hold PTL in pagemap_hugetlb_range and gather_hugetlb_stats

Hold PTL in pagemap_hugetlb_range() and gather_hugetlb_stats() to avoid
operating on stale page, as pagemap_pmd_range() and gather_pte_stats()
have done.

Link: https://lkml.kernel.org/r/20250724090958.455887-3-tujinjiang@huawei.com
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Brahmajit Das <brahmajit.xyz@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joern Engel <joern@logfs.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 55bab10bc779aeac9103a1fee059dbb3b45d788d..ee1e4ccd33bd6f4b2d5687e7122958b11aba1800 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -2021,12 +2021,14 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
        struct pagemapread *pm = walk->private;
        struct vm_area_struct *vma = walk->vma;
        u64 flags = 0, frame = 0;
+       spinlock_t *ptl;
        int err = 0;
        pte_t pte;
 
        if (vma->vm_flags & VM_SOFTDIRTY)
                flags |= PM_SOFT_DIRTY;
 
+       ptl = huge_pte_lock(hstate_vma(vma), walk->mm, ptep);
        pte = huge_ptep_get(walk->mm, addr, ptep);
        if (pte_present(pte)) {
                struct folio *folio = page_folio(pte_page(pte));
@@ -2054,11 +2056,12 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 
                err = add_to_pagemap(&pme, pm);
                if (err)
-                       return err;
+                       break;
                if (pm->show_pfn && (flags & PM_PRESENT))
                        frame++;
        }
 
+       spin_unlock(ptl);
        cond_resched();
 
        return err;
@@ -3132,17 +3135,22 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
                unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
-       pte_t huge_pte = huge_ptep_get(walk->mm, addr, pte);
+       pte_t huge_pte;
        struct numa_maps *md;
        struct page *page;
+       spinlock_t *ptl;
 
+       ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
+       huge_pte = huge_ptep_get(walk->mm, addr, pte);
        if (!pte_present(huge_pte))
-               return 0;
+               goto out;
 
        page = pte_page(huge_pte);
 
        md = walk->private;
        gather_stats(page, md, pte_dirty(huge_pte), 1);
+out:
+       spin_unlock(ptl);
        return 0;
 }