copy_to_user_nofault(9)

Bestie, this is the copy_to_user_nofault(9) page from the Kernel API Manual 💖 buckle up, it’s a short one but it’s lowkey important.

🌸 NAME 🌸

copy_to_user_nofault — safely attempt to write to a user-space location. That’s the whole assignment, and it ate. 💅

✨ SYNOPSIS ✨

long copy_to_user_nofault (void __user *dst , const void *src , size_t
       size );

🎀 ARGUMENTS 🎀

• dst — address to write to. The target, the destination, the spot. 🎯
• src — pointer to the data that shall be written. This is where the bytes are coming from. 🫶
• size — size of the data chunk. How big the chunk is. 📏

💅 DESCRIPTION 💅

Okay so here’s the tea: safely write to address dst from the buffer at src. 🫖

If a kernel fault happens, handle that and return -EFAULT. That’s it. That’s the behavior. Iconic, honestly. 😭

No cap: -EFAULT is the return you get when that kernel fault situation happens. Keep it in mind. 💀

🦋 SEE ALSO 🦋

• Kernel file ./mm/maccess.c
• copy_from_user_nofault(9)
• strncpy_from_user_nofault(9)
• strnlen_user_nofault(9)

That’s the whole page, bestie 🫶 source/version: ./mm, date: October 2026, title: copy_to_user_nofault(9). Mwah 💋✨