copy_remote_vm_str(9)

💅 copy_remote_vm_str(9) — from the Kernel API Manual, bestie ✨

Okay so picture this: it's a (9) page straight out of the Kernel API Manual, and it's all about yoinking a string out of somebody else's address space. Yes, another process. Yes, that's the whole vibe. 🫶

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🌸 NAME 🌸

copy_remote_vm_str — literally just copy a string from another process's address space. That's it. That's the function. 💖

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✨ SYNOPSIS ✨

int copy_remote_vm_str (struct task_struct *tsk , unsigned long addr ,
       void *buf , int len , unsigned int gup_flags );

Five arguments, one int coming back at you. Iconic. 👑

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🎀 ARGUMENTS 🎀

• tsk — the task whose address space we're snooping through. It's giving "the target address space" main character energy.
• addr — where you start reading from. The starting line. 🏁
• buf — the destination buffer, aka where the string lands. Your emotional support buffer.
• len — how many bytes you're copying. Count 'em. 🔢
• gup_flags — flags that modify lookup behaviour. And here's the tea: they're unused 💀. Present, accounted for, not doing anything.

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🦋 DESCRIPTION 🦋

Okay so the one thing you absolutely cannot forget: the caller must hold a reference on mm. That's not a suggestion, that's the rule. Hold the reference. No cap. 🔥

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🌈 RETURN 🌈

What you get back is the number of bytes copied from addr (the source) over to buf (the destination) — and ngl, that count does not include the trailing NUL.

Also, bestie, a guarantee: it always leaves you with a NUL-terminated buffer. Always. 🎁

But if anything goes sideways on any error? You get -EFAULT. That's it. That's the whole error story. 😭

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⭐ SEE ALSO ⭐

Kernel file ./mm/nommu.c, plus these besties:

• vmalloc_node(9)
• vzalloc_node(9)
• vmalloc_32(9)
• vmalloc_32_user(9)
• access_remote_vm(9)
• nommu_shrink_inode_mappings(9)

iykyk 💜

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🧚 Friendly little reminder from me to you: hold that mm reference. Seriously. 🙈

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Sign-off time, bestie 🍓 — this page lives in the source directory ./mm, it's dated October 2026, and it's filed under copy_remote_vm_str(9) in the Kernel API Manual. Slay, go copy some strings. 💅✨