task_current_syscall(9)

✨ task_current_syscall(9) ✨

ok so this is a page from the Kernel API Manual, section 9, and it's literally called task_current_syscall — bestie, it lets you peek at what a blocked task is actually doing 💅

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🌸 NAME 🌸

task_current_syscall — discover what a blocked task is doing 👀

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🦋 SYNOPSIS 🦋

int task_current_syscall (struct task_struct *target , struct syscall_info *info );

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🎀 ARGUMENTS 🎀

• target — the thread to examine 🔍 (yes, that thread, the one you're being nosy about)
• info — a structure with these fields, and bestie, pay attention to each one:
  • .sp — filled with the user stack pointer 🧚
  • .data.nr — filled with the system call number, or -1 💀
  • .data.args — filled with the maxargs system call arguments 🍓
  • .data.instruction_pointer — filled with the user PC ⭐

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💜 DESCRIPTION 💜

So here's the vibe: if target is blocked in a system call, this returns zero, with info.data.nr set to the call's number and info.data.args filled in with its arguments. 🫶 Registers not used for system call arguments may not be available, and listen — it is not kosher to use struct user_regset calls while the system call is still in progress. 🙈 Ngl, that's the rules.

Heads up: we may get this result if target has finished its system call but not yet returned to user mode — like when it's stopped for signal handling or syscall exit tracing. So don't @ me if it looks done but isn't done done. 😭

Now, if target is blocked in the kernel during a fault or exception, it returns zero with *info.data.nr set to -1 and does not fill in info.data.args. 🌈 But good news: if that's the case, it's now safe to examine target using struct user_regset get calls — as long as we're sure target won't return to user mode. 👑

And if target does not remain blocked? Returns -EAGAIN. Periodt. 💀

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🔥 SEE ALSO 🔥

• Kernel file ./lib/syscall.c — go read it, iykyk 📖

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and that's the whole manual, no cap ✨

kisses, this page came from ./lib, dated October 2026, and it'll live forever in your heart as task_current_syscall(9) 💖🎀🦋