call_usermodehelper_setup(9)

call_usermodehelper_setup(9) 💖

okay so this is the Kernel API Manual page for call_usermodehelper_setup(9) — bestie, we're getting a usermode helper all ready to go, and it's giving very much “setup era” 🎀✨

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🌸 NAME 🌸

call_usermodehelper_setup — prepare to call a usermode helper 🫶

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🦋 SYNOPSIS 🦋

struct subprocess_info * call_usermodehelper_setup (const char *path ,
char **argv , char **envp , gfp_t gfp_mask , int (*init)(struct
subprocess_info *info, struct cred *new) , void (*cleanup)(struct
subprocess_info *info) , void *data );

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✨ ARGUMENTS ✨

• path — path to usermode executable 👑
• argv — arg vector for process 🧚
• envp — environment for process 🌈
• gfp_mask — gfp mask for memory allocation 💜
• init — an init function ⭐
• cleanup — a cleanup function 🎀
• data — arbitrary context sensitive data 🍓

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💅 DESCRIPTION 💅

So it returns either NULL on allocation failure, or a subprocess_info structure — no cap. That structure should be passed to call_usermodehelper_exec to exec the process and free the structure. periodt ✅

The init function is used to customize the helper process prior to exec. A non-zero return code causes the process to error out, exit, and return the failure to the calling process 😭🔥

The cleanup function is just before the subprocess_info is about to be freed. This can be used for freeing the argv and envp — very “clean up your own mess” icon behavior 💖 The Function (yes, capital F, bestie) must be runnable in either a process context or the context in which call_usermodehelper_exec is called. iykyk 👀

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🔥 SEE ALSO 🔥

Kernel file ./kernel/umh.c — and then the whole squad:

• __usermodehelper_set_disable_depth(9)
• __usermodehelper_disable(9)
• call_usermodehelper_exec(9)
• call_usermodehelper(9)

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mwah 💋 — source/version: ./kernel, date: October 2026, page: call_usermodehelper_setup(9) 🫶✨