finish_fault(9)

💅 finish_fault(9) — like, the Kernel API Manual page you actually wanna read ✨

okay so this is finish_fault(9) from the Kernel API Manual, and bestie, it's literally the "last mile" of a page fault 🎀

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🌸 NAME 🌸

finish_fault — the function that finishes the page fault once we've already prepared the page we're faulting in. slay, closure 💅

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✨ SYNOPSIS ✨

vm_fault_t finish_fault (struct vm_fault *vmf );

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🫶 ARGUMENTS 🫶

• vmf — the structure that describes the fault. it's giving "everything you need to know about what just went down" 💖

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🔥 DESCRIPTION 🔥

so here's the vibe 👑: this function handles all the stuff that's needed to wrap up a page fault once the page to fault in is already prepared. it does not prepare the page — that part's already done — it just brings it home 🏠✨

what it actually handles, no cap:

• locking of PTEs 🔒
• inserting the PTE for the given page 📌
• adding reverse page mapping 🔁
• handling memcg charges 💸
• LRU addition 📚

important caveat, fr fr: the function expects the page to be locked going in, and on success it consumes a reference of a page being mapped — that's for the PTE which maps it. don't come for it later expecting that ref back, it's gone 💀

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⭐ RETURN ⭐

• 0 on success 🎉
• a VM_FAULT_ code in case of error 😭

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🌈 SEE ALSO 🌈

all the friends in the kernel file ./mm/memory.c — go say hi to the whole group chat 🧚:

• free_pgd_range(9)
• free_pgtables(9)
• __vm_normal_page(9)
• vm_normal_page(9)
• vm_normal_folio(9)
• vm_normal_page_pmd(9)
• vm_normal_folio_pmd(9)
• vm_normal_page_pud(9)
• restore_exclusive_pte(9)
• cond_install_uffd_wp_ptes(9)
• zap_vma_for_reaping(9)
• unmap_vmas(9)
• zap_vma_range_batched(9)
• zap_vma_range(9)
• zap_special_vma_range(9)
• vm_insert_pages(9)
• vm_insert_page(9)
• vm_map_pages(9)
• vm_map_pages_zero(9)
• vmf_insert_pfn_prot(9)
• vmf_insert_pfn(9)
• remap_pfn_range(9)
• vm_iomap_memory(9)
• __vmf_anon_prepare(9)
• finish_mkwrite_fault(9)
• unmap_mapping_folio(9)
• unmap_mapping_pages(9)
• unmap_mapping_range(9)
• set_pte_range(9)
• mm_account_fault(9)
• follow_pfnmap_start(9)
• follow_pfnmap_end(9)
• generic_access_phys(9)
• access_remote_vm(9)
• copy_remote_vm_str(9)
• folio_zero_user(9)

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and that's the whole page, babe 🫶 that's it, that's the fault 💅 — this came to you from ./mm, dated October 2026, in the Kernel API Manual. mwah, go finish some faults 🎀✨🍓