pin_user_pages(9)

💅 pin_user_pages — bestie's guide to the kernel API manual, section 9, no cap 🫶

Okay so picture this: you're in the Kernel API Manual (that's the 9 section, iykyk) and you need to pin user pages in memory so other devices can use them. That's literally the whole vibe of pin_user_pages. Let's get into it ✨

---

🎀 NAME 🎀

pin_user_pages — pin user pages in memory for use by other devices 💖

🌸 SYNOPSIS 🌸

long pin_user_pages (unsigned long start , unsigned long nr_pages ,
       unsigned int gup_flags , struct page **pages );

🦋 ARGUMENTS 🦋

• start — the starting user address. Where the whole thing kicks off, bestie 📍
• nr_pages — number of pages from start to pin. Like, how many pages we're grabbing, starting from start 🌈
• gup_flags — flags that modify the lookup behaviour. These little guys change how the whole search goes down ⭐
• pages — the array that receives pointers to the pages pinned. Heads up though: it should be at least nr_pages long, so don't be out here under-sizing it 🙈

👑 DESCRIPTION 👑

Okay so this one is nearly the same as get_user_pages, except (and this is the iconic part, lowkey the whole personality of the function):

• FOLL_TOUCH is not set
• FOLL_PIN is set

And what does FOLL_PIN mean for you, queen? It means those pages must be released via unpin_user_page. No cap, that's not optional — that's the whole release path 💀

If you want the full lore, please see Documentation/core-api/pin_user_pages.rst for details. The docs ate, fr fr 📚

Also, super important detail: note that if a zero_page is amongst the returned pages, it will not have pins in it, and unpin_user_page*() will not remove pins from it. So don't come for that page expecting pins that were never there 🫶

🔥 SEE ALSO 🔥

Kernel file ./mm/gup.c, plus the whole friend group: try_grab_folio(9), unpin_user_page(9), unpin_folio(9), folio_add_pin(9), unpin_user_pages_dirty_lock(9), unpin_user_page_range_dirty_lock(9), unpin_user_pages(9), unpin_user_folio(9), unpin_folios(9), try_grab_folio_fast(9), follow_page_mask(9), __get_user_pages(9), fixup_user_fault(9), populate_vma_page_range(9), fault_in_writeable(9), fault_in_subpage_writeable(9), fault_in_readable(9), get_dump_page(9), get_user_pages_remote(9), get_user_pages(9), get_user_pages_fast_only(9), get_user_pages_fast(9), pin_user_pages_fast(9), pin_user_pages_remote(9), memfd_pin_folios(9), folio_add_pins(9)

---

And that's the whole page, bestie! 💜 Shoutout to the ./mm source and the October 2026 date — that's the version stamp, slay ✨ Go pin some pages responsibly, and remember: unpin them or it's giving leak 💅🎀