vmalloc_32_user(9)

💅 vmalloc_32_user(9) 💅

okay so this is a page from the Kernel API Manual, and bestie, we're about to get into it. sit down, grab a strawberry 🍓, and let's talk about getting yourself some zeroed, virtually contiguous, 32-bit addressable memory.

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✨ NAME ✨

vmalloc_32_user — allocate zeroed virtually contiguous 32bit memory 🎀

literally the whole vibe in one line: you get memory, it's virtual, it's contiguous, it's 32-bit, and it's zeroed. slay.

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🌸 SYNOPSIS 🌸

void * vmalloc_32_user (unsigned long size );

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🦋 ARGUMENTS 🦋

• size — the allocation size. how much memory you want. that's it, that's the whole argument, she's lowkey simple like that 💅

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👑 DESCRIPTION 👑

ok so the memory area you get back is 32bit addressable and it's zeroed — and that second part is doing so much work for you, because it means the area can be mapped to userspace without leaking data. no stale garbage from some other process just vibing in your pages. iconic behaviour, honestly 🫶

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⭐ RETURN ⭐

a pointer to the allocated memory ✨ — or NULL on error 😭 (yes, you have to check it, no cap, always check it).

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🌈 SEE ALSO 🌈

the whole friend group, in the order the page lists them, and yes we're naming every single one because nobody gets left out:

Kernel file ./mm/vmalloc.c and then: vunmap_range(9), vmap_pages_range(9), vm_area_map_pages(9), vm_area_unmap_pages(9), new_vmap_block(9), vm_unmap_aliases(9), vm_unmap_ram(9), vm_map_ram(9), vm_area_add_early(9), vm_area_register_early(9), get_vm_area(9), find_vm_area(9), remove_vm_area(9), vfree_atomic(9), vfree(9), vunmap(9), vmap(9), vmap_pfn(9), __vmalloc_node_range(9), __vmalloc_node(9), vmalloc(9), vmalloc_huge_node(9), vzalloc(9), vmalloc_user(9), vmalloc_node(9), vzalloc_node(9), vrealloc_node_align(9), vmalloc_32(9), vread_iter(9), remap_vmalloc_range_partial(9), remap_vmalloc_range(9), pvm_find_va_enclose_addr(9), pvm_determine_end_from_reverse(9), pcpu_get_vm_areas(9), pcpu_free_vm_areas(9).

like I said. the whole group chat. 💀

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ngl if you're mapping this into userspace, the zeroing is the entire point — don't go skipping past it 🙈

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and that's the page!! mwah 💖 this little number lives in ./mm and it's dated October 2026, so go forth, allocate your 32-bit zeroed contiguous memory, and remember: check for NULL, bestie. periodt. 🧚‍♀️✨