Commit 80868f5d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cgroup-for-6.14-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup fixes from Tejun Heo:

 - Fix a race window where a newly forked task could escape cgroup.kill

 - Remove incorrectly included steal time from cpu.stat::usage_usec

 - Minor update in selftest

* tag 'cgroup-for-6.14-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: Remove steal time from usage_usec
  selftests/cgroup: use bash in test_cpuset_v1_hp.sh
  cgroup: fix race between fork and cgroup.kill
parents f4d46809 db5fd3cf

include/linux/cgroup-defs.h

+3 −3
Original line number Diff line number Diff line
@@ -71,9 +71,6 @@ enum { 


	/* Cgroup is frozen. */

	CGRP_FROZEN,



	/* Control group has to be killed. */

	CGRP_KILL,

};



/* cgroup_root->flags */
@@ -461,6 +458,9 @@ struct cgroup { 


	int nr_threaded_children;	/* # of live threaded child cgroups */



	/* sequence number for cgroup.kill, serialized by css_set_lock. */

	unsigned int kill_seq;



	struct kernfs_node *kn;		/* cgroup kernfs entry */

	struct cgroup_file procs_file;	/* handle for "cgroup.procs" */

	struct cgroup_file events_file;	/* handle for "cgroup.events" */

include/linux/sched/task.h

+1 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ struct kernel_clone_args { 
	void *fn_arg;

	struct cgroup *cgrp;

	struct css_set *cset;

	unsigned int kill_seq;

};



/*

kernel/cgroup/cgroup.c

+12 −8
Original line number Diff line number Diff line
@@ -4013,7 +4013,7 @@ static void __cgroup_kill(struct cgroup *cgrp) 
	lockdep_assert_held(&cgroup_mutex);



	spin_lock_irq(&css_set_lock);

	set_bit(CGRP_KILL, &cgrp->flags);

	cgrp->kill_seq++;

	spin_unlock_irq(&css_set_lock);



	css_task_iter_start(&cgrp->self, CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED, &it);
@@ -4029,10 +4029,6 @@ static void __cgroup_kill(struct cgroup *cgrp) 
		send_sig(SIGKILL, task, 0);

	}

	css_task_iter_end(&it);



	spin_lock_irq(&css_set_lock);

	clear_bit(CGRP_KILL, &cgrp->flags);

	spin_unlock_irq(&css_set_lock);

}



static void cgroup_kill(struct cgroup *cgrp)
@@ -6488,6 +6484,10 @@ static int cgroup_css_set_fork(struct kernel_clone_args *kargs) 
	spin_lock_irq(&css_set_lock);

	cset = task_css_set(current);

	get_css_set(cset);

	if (kargs->cgrp)

		kargs->kill_seq = kargs->cgrp->kill_seq;

	else

		kargs->kill_seq = cset->dfl_cgrp->kill_seq;

	spin_unlock_irq(&css_set_lock);



	if (!(kargs->flags & CLONE_INTO_CGROUP)) {
@@ -6668,6 +6668,7 @@ void cgroup_post_fork(struct task_struct *child, 
		      struct kernel_clone_args *kargs)

	__releases(&cgroup_threadgroup_rwsem) __releases(&cgroup_mutex)

{

	unsigned int cgrp_kill_seq = 0;

	unsigned long cgrp_flags = 0;

	bool kill = false;

	struct cgroup_subsys *ss;
@@ -6681,10 +6682,13 @@ void cgroup_post_fork(struct task_struct *child, 


	/* init tasks are special, only link regular threads */

	if (likely(child->pid)) {

		if (kargs->cgrp)

		if (kargs->cgrp) {

			cgrp_flags = kargs->cgrp->flags;

		else

			cgrp_kill_seq = kargs->cgrp->kill_seq;

		} else {

			cgrp_flags = cset->dfl_cgrp->flags;

			cgrp_kill_seq = cset->dfl_cgrp->kill_seq;

		}



		WARN_ON_ONCE(!list_empty(&child->cg_list));

		cset->nr_tasks++;
@@ -6719,7 +6723,7 @@ void cgroup_post_fork(struct task_struct *child, 
		 * child down right after we finished preparing it for

		 * userspace.

		 */

		kill = test_bit(CGRP_KILL, &cgrp_flags);

		kill = kargs->kill_seq != cgrp_kill_seq;

	}



	spin_unlock_irq(&css_set_lock);

kernel/cgroup/rstat.c

+0 −1
Original line number Diff line number Diff line
@@ -590,7 +590,6 @@ static void root_cgroup_cputime(struct cgroup_base_stat *bstat) 


		cputime->sum_exec_runtime += user;

		cputime->sum_exec_runtime += sys;

		cputime->sum_exec_runtime += cpustat[CPUTIME_STEAL];



#ifdef CONFIG_SCHED_CORE

		bstat->forceidle_sum += cpustat[CPUTIME_FORCEIDLE];

tools/testing/selftests/cgroup/test_cpuset_v1_hp.sh

+1 −1
Original line number Diff line number Diff line 
#!/bin/sh

#!/bin/bash

# SPDX-License-Identifier: GPL-2.0

#

# Test the special cpuset v1 hotplug case where a cpuset become empty of