syscall_set_nr(9)

✨ syscall_set_nr ✨

okay bestie, so this one is a <purple>kernel API</purple> page from the Kernel API Manual (<cyan>syscall_set_nr(9)</cyan>, section 9, iykyk) and it's literally about swapping out which system call a task is running 🎀

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🌸 NAME 🌸

syscall_set_nr — change the system call a task is executing 💅

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🦋 SYNOPSIS 🦋

void syscall_set_nr (struct task_struct *task , struct pt_regs *regs ,
int nr );

like, that's the whole signature, no cap ✨

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💖 ARGUMENTS 💖

• task — the task of interest, and bestie it must be blocked 🫶
• regs — the task_pt_regs of that task
• nr — the system call number 🎀

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👑 DESCRIPTION 👑

So what it does: it changes the system call number that task is about to execute. Slay. 💅

⚠️ but listen, it's only valid to call this when task is stopped for tracing on entry to a system call, due to SYSCALL_WORK_SYSCALL_TRACE or SYSCALL_WORK_SYSCALL_AUDIT. That's the vibe check and it is not optional, fr fr.

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🌈 SEE ALSO 🌈

Kernel file ./include/asm-generic/syscall.h plus the whole friend group:

• syscall_get_nr(9)
• syscall_rollback(9)
• syscall_get_error(9)
• syscall_get_return_value(9)
• syscall_set_return_value(9)
• syscall_get_arguments(9)
• syscall_set_arguments(9)
• syscall_get_arch(9)

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okay that's the whole page bestie, mwah 💋 this iconic little entry lives in ./include/asm-generic in the Kernel API Manual, dated <lavender>October 2026</lavender> — go be the main character of your own syscall tracing era 🧚‍♀️💜