cgroup_can_fork(9)

💅 cgroup_can_fork(9) 💅

okay so this is a page from the Kernel API Manual, and it's about cgroup_can_fork — the little gatekeeper that gets a say before your brand-new task ever gets exposed to the world. main character energy fr fr 🎀

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✨ SYNOPSIS ✨

int cgroup_can_fork (struct task_struct *child , struct
kernel_clone_args *kargs );

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🌸 ARGUMENTS 🌸

• child — the child process 🍼 like, the actual new baby task being born
• kargs — the arguments that got passed in to create that child process, the whole origin story basically

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💖 DESCRIPTION 💖

So here's the vibe: this function prepares a fresh new css_set for the child process — and that's the css_set the child is gonna get attached to later, over in cgroup_post_fork. ✨

While it's doing that, it also calls the subsystem can_fork callbacks. Think of it as the bouncer checking the guest list 👑

💀 and here's the important bit, bestie: if the cgroup_can_fork callback returns an error, the fork aborts with that error code. Like, the whole thing. Not me being dramatic, that's literally what it says.

Which is exactly the point — it lets a cgroup subsystem conditionally allow or deny new forks. Slay, honestly. Consent matters. 🫶

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🦋 SEE ALSO 🦋

Kernel file ./kernel/cgroup/cgroup.c

cgroup_ssid_enabled(9), cgroup_on_dfl(9), cgroup_e_css_by_mask(9), cgroup_e_css(9), cgroup_get_e_css(9), __cgroup_task_count(9), cgroup_task_count(9), for_each_css(9), do_each_subsys_mask(9), css_set_populated(9), css_update_populated(9), css_set_update_populated(9), css_set_move_task(9), compare_css_sets(9), find_existing_css_set(9), allocate_cgrp_cset_links(9), link_css_set(9), find_css_set(9), cgroup_file_mode(9), cgroup_calc_subtree_ss_mask(9), cgroup_kn_unlock(9), cgroup_kn_lock_live(9), css_clear_dir(9), css_populate_dir(9), cgroup_attach_lock(9), cgroup_attach_unlock(9), cgroup_migrate_add_task(9), cgroup_taskset_first(9), cgroup_taskset_next(9), cgroup_migrate_execute(9), cgroup_migrate_vet_dst(9), cgroup_migrate_finish(9), cgroup_migrate_add_src(9), cgroup_migrate_prepare_dst(9), cgroup_migrate(9), cgroup_attach_task(9), cgroup_update_dfl_csses(9), cgroup_lock_and_drain_offline(9), cgroup_save_control(9), cgroup_propagate_control(9), cgroup_restore_control(9), cgroup_apply_control_enable(9), cgroup_apply_control_disable(9), cgroup_apply_control(9), cgroup_finalize_control(9), cgroup_enable_threaded(9), cgroup_tryget_css(9), cgroup_addrm_files(9), cgroup_rm_cftypes(9), cgroup_add_cftypes(9), cgroup_add_dfl_cftypes(9), cgroup_add_legacy_cftypes(9), cgroup_file_notify(9), cgroup_file_show(9), css_next_child(9), css_next_descendant_pre(9), css_rightmost_descendant(9), css_next_descendant_post(9), css_has_online_children(9), css_task_iter_advance_css_set(9), css_task_iter_start(9), css_task_iter_next(9), css_task_iter_end(9), css_create(9), kill_css_sync(9), kill_css_finish(9), cgroup_destroy_locked(9), cgroup_init_early(9), cgroup_init(9), cgroup_fork(9), cgroup_v1v2_get_from_file(9), cgroup_get_from_file(9), cgroup_css_set_fork(9), cgroup_css_set_put_fork(9), cgroup_cancel_fork(9), cgroup_post_fork(9), cgroup_task_exit(9), css_tryget_online_from_dir(9), css_from_id(9), cgroup_get_from_path(9), cgroup_v1v2_get_from_fd(9), cgroup_get_from_fd(9), cgroup_parse_float(9)

ok that's a lot of friends but they're all invited to the group chat 💀 no cap, every single one of them.

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that's the whole page bestie, you ate that 🍓✨

signing off from ./kernel/cgroup — this edition dropped back in October 2026, so you already know it's iconic 👑💜