task_css_set_check(9)

📦 version 7.3.1, in nixpkgs unstable

💅 task_css_set_check(9) ✨

okay so bestie, welcome to the kernel API manual — this one's a macro page, and honestly? she's kind of a vibe. buckle up 🎀

🌸 NAME 🌸

task_css_set_check — literally just: obtain a task's css_set, but with extra access conditions baked in. that's the whole assignment 💖

✨ SYNOPSIS ✨

task_css_set_check (task , __c );

yes, the spacing is real, no i'm not fixing it, that's how she's written 💅

🫶 ARGUMENTS 🫶

  • task — the task you wanna get the css_set for. the main character, if you will 👑
  • __c — an extra condition expression, and it gets passed straight to rcu_dereference_check. so like, your little bonus vibe check 🙈

🔥 DESCRIPTION 🔥

so a task's css_set is RCU protected — meaning it's got that read-copy-update energy protecting it 💜 and it gets initialized and exited while holding task_lock. also, it can only be modified while holding both cgroup_mutex and task_lock, and only while the task is still alive. not me being strict about the lock order 😭

what this macro does: it verifies that the caller is actually inside a proper critical section, then returns the task's css_set. that's it. that's the whole thing. it's giving bouncer-at-the-club checking your ID before letting you in 🎀

and because life isn't one-size-fits-all, the caller can also pass additional allowed conditions via __c — like the locks used during the cgroup_subsys::attach methods. so basically you can tell her "hey, i also have this lock, that's fiiiine" ✨

🌈 SEE ALSO 🌈

kernel file ./include/linux/cgroup.h, plus the whole friend group:

ok and one genuine heads-up bestie: this is a check macro, so the "proper critical section" thing is not decorative — it's asserting your locking is correct. don't be out here calling it from nowhere and then acting surprised 💀

and that's the page!! sourced from ./include/linux, dated October 2026, filed under task_css_set_check(9) — slay, go read your locks, ily 🦋💖🌟

📦 where this page comes from