check_pte(9)

💅 check_pte(9) — the kernel API manual, bestie edition

okay so real talk, this one lives in section 9 of the kernel API manual and it's literally called check_pte. yes bestie, we're doing pointer-checking lore today 🎀

✨ NAME ✨

check_pte — check if [pvmw->pfn, @pvmw->pfn + @pvmw->nr_pages) is mapped at the @pvmw->pte

like, is this range actually there or are we delulu? that's the whole job 💅

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🦋 SYNOPSIS 🦋

bool check_pte (struct page_vma_mapped_walk *pvmw , unsigned long pte_nr
);

returns a bool, takes two things, that's the vibe ✨

🌸 ARGUMENTS 🌸

• pvmw — a page_vma_mapped_walk struct, and it's carrying a cute little pair for you: a pte and a pfn range, and that range is what we're checking, no cap 🫶
• pte_nr — the number of small pages described by pvmw->pte. tiny page headcount, basically 🍓

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👑 DESCRIPTION 👑

so page_vma_mapped_walk found a spot where the pfn range is potentially mapped. potential is not the same as real, bestie 😭 that's why check_pte exists — it has to validate this. vibe check time, fr fr.

pvmw->pte may point to an empty PTE, a swap PTE, or a PTE pointing to an arbitrary page. so like… it could be anything. main character energy but unconfirmed 💀

if the PVMW_MIGRATION flag is set, it returns true if pvmw->pte contains a migration entry that points to [pvmw->pfn, pvmw->pfn + pvmw->nr_pages) 🔥

if the PVMW_MIGRATION flag is not set, it returns true if pvmw->pte points to [pvmw->pfn, pvmw->pfn + pvmw->nr_pages) ⭐

otherwise? return false. that's it, that's the whole plot 🙈

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🧚 SEE ALSO 🧚

• Kernel file ./mm/page_vma_mapped.c page_vma_mapped_walk(9)
• page_mapped_in_vma(9)

iykyk, go read those next, the whole friend group is iconic 💜

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and that's a wrap, bestie 🎀 this page came from ./mm, October 2026, and it's served with love — now go validate those PTEs, slay ✨