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fs/proc/task_mmu: fix PAGE_IS_PFNZERO detection for the huge zero folio

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commit 4a5e85f4eb8fd18b1266342d100e4f0849544ca0 upstream.

is_zero_pfn() does not work for the huge zero folio. Fix it by using
is_huge_zero_pmd().

This can cause the PAGEMAP_SCAN ioctl against /proc/pid/pagemap to
present pages as PAGE_IS_PRESENT rather than as PAGE_IS_PFNZERO.

Found by code inspection.

Link: https://lkml.kernel.org/r/20250617143532.2375383-1-david@redhat.com
Fixes: 52526ca7fd ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
David Hildenbrand
2025-06-17 16:35:32 +02:00
committed by Greg Kroah-Hartman
parent f855b119e6
commit 93abf5e0d5
1 changed files with 1 additions and 1 deletions
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2
fs/proc/task_mmu.c
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@@ -2155,7 +2155,7 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
categories |= PAGE_IS_FILE;
}
if (is_zero_pfn(pmd_pfn(pmd)))
if (is_huge_zero_pmd(pmd))
categories |= PAGE_IS_PFNZERO;
if (pmd_soft_dirty(pmd))
categories |= PAGE_IS_SOFT_DIRTY;