__put_user(9)

🌸 __put_user(9) 🌸

hey bestie, welcome to the Kernel API Manual — today’s main character is __put_user(9), and she is lowkey here to write one simple value into user space with less checking. no cap. 🫶

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✨ NAME ✨

__put_user — write a simple value into user space, with less checking. 💅

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🎀 SYNOPSIS 🎀

__put_user (x , ptr );

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🦋 ARGUMENTS 🦋

• x — the value to copy to user space. literally the thing being sent over. 💌
• ptr — the destination address, in user space. that’s where x is going, bestie. 📍

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💜 CONTEXT 💜

user context only, okay? 👑 this function may sleep if pagefaults are enabled — so don’t be weird about it. 😴

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💖 DESCRIPTION 💖

okay so this macro copies a single simple value from kernel space to user space. it supports simple types like char and int, but not larger data types like structures or arrays — so leave your big complicated faves at home, this is a one-value situation. ✨

ptr must have pointer-to-simple-variable type, and x must be assignable to the result of dereferencing ptr. that’s the vibe check for the types, fr fr. 🧚

🚨 caller must check the pointer with access_ok before calling this function. not optional, bestie — do the check first. 💀

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🔥 RETURN 🔥

zero on success, or -EFAULT on error. that’s it, that’s the whole report card. 😭

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🌈 SEE ALSO 🌈

• Kernel file ./arch/x86/include/asm/uaccess.h
• get_user(9)
• __get_user(9)
• put_user(9)

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catch u later, mwah 💅 — this cutie came from ./arch/x86/include/asm, October 2026, and yes she ate. 🍓👑