clear_user_pages(9)

💅 clear_user_pages — the kernel API manual, bestie edition 💅

okay so real talk, this one is a Kernel API Manual page (iykyk), and it's about clear_user_pages. strap in 🎀

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✨ NAME ✨

clear_user_pages — clears a page range so it can be mapped into user space. yes bestie, we're zeroing pages before they go hang out with userspace 👑

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🌸 SYNOPSIS 🌸

void clear_user_pages (void *addr , unsigned long vaddr , struct page
*page , unsigned int npages );

literally the whole signature, no notes, copy it exactly 💖

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🦋 ARGUMENTS 🦋

• addr — the start address. that's it, that's the vibe ✨
• vaddr — the start address of the user mapping (different address, same energy 🌈)
• page — the start page
• npages — how many pages we're talking about 👑

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💜 DESCRIPTION 💜

okay so here's the tea ☕ — this function assumes the region (addr, +npages) has already been validated. like, somebody else did the vibe check already. so it does no exception handling. none. zero. not a single one 🙈 that's not a bug, that's just the contract, bestie.

and then: if the architecture provides a clear_user_page, use that one — slay, use the native one 💅. otherwise, we can safely use clear_pages. iconic fallback behaviour, no cap 🫶

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⭐ SEE ALSO ⭐

the whole friend group 🎀 — kernel file ./include/linux/highmem.h, plus:

• kmap(9)
• kunmap(9)
• kmap_to_page(9)
• kmap_flush_unused(9)
• kmap_local_page(9)
• kmap_local_folio(9)
• kmap_atomic(9)
• clear_user_page(9)
• clear_user_highpage(9)
• clear_user_highpages(9)
• vma_alloc_zeroed_movable_folio(9)
• memcpy_from_folio(9)
• memcpy_to_folio(9)
• folio_zero_tail(9)
• folio_fill_tail(9)
• memcpy_from_file_folio(9)
• folio_zero_segments(9)
• folio_zero_segment(9)
• folio_zero_range(9)
• folio_release_kmap(9)

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💀 reminder bestie: the no-exception-handling thing is load-bearing — that region better be validated before you call this, fr fr.

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and that's the page!! sign-off time 🎀 this one lives over in ./include/linux, dated October 2026, and it's filed under clear_user_pages(9). mwah, go clear some pages 💖✨🦋