Commit c1ad41f1 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

Revert "sched/autogroup: Fix crash on reboot when autogroup is disabled" 



This reverts commit 5258f386,
because the underlying autogroups bug got fixed upstream in
a better way, via:

  fd8ef117 Revert "sched, autogroup: Stop going ahead if autogroup is disabled"

Cc: Mike Galbraith <efault@gmx.de>
Cc: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 38130ec0

fs/proc/base.c

+78 −0
Original line number Diff line number Diff line
@@ -1272,6 +1272,81 @@ static const struct file_operations proc_pid_sched_operations = { 


#endif



#ifdef CONFIG_SCHED_AUTOGROUP

/*

 * Print out autogroup related information:

 */

static int sched_autogroup_show(struct seq_file *m, void *v)

{

	struct inode *inode = m->private;

	struct task_struct *p;



	p = get_proc_task(inode);

	if (!p)

		return -ESRCH;

	proc_sched_autogroup_show_task(p, m);



	put_task_struct(p);



	return 0;

}



static ssize_t

sched_autogroup_write(struct file *file, const char __user *buf,

	    size_t count, loff_t *offset)

{

	struct inode *inode = file->f_path.dentry->d_inode;

	struct task_struct *p;

	char buffer[PROC_NUMBUF];

	int nice;

	int err;



	memset(buffer, 0, sizeof(buffer));

	if (count > sizeof(buffer) - 1)

		count = sizeof(buffer) - 1;

	if (copy_from_user(buffer, buf, count))

		return -EFAULT;



	err = kstrtoint(strstrip(buffer), 0, &nice);

	if (err < 0)

		return err;



	p = get_proc_task(inode);

	if (!p)

		return -ESRCH;



	err = proc_sched_autogroup_set_nice(p, nice);

	if (err)

		count = err;



	put_task_struct(p);



	return count;

}



static int sched_autogroup_open(struct inode *inode, struct file *filp)

{

	int ret;



	ret = single_open(filp, sched_autogroup_show, NULL);

	if (!ret) {

		struct seq_file *m = filp->private_data;



		m->private = inode;

	}

	return ret;

}



static const struct file_operations proc_pid_sched_autogroup_operations = {

	.open		= sched_autogroup_open,

	.read		= seq_read,

	.write		= sched_autogroup_write,

	.llseek		= seq_lseek,

	.release	= single_release,

};



#endif /* CONFIG_SCHED_AUTOGROUP */



static ssize_t comm_write(struct file *file, const char __user *buf,

				size_t count, loff_t *offset)

{
@@ -2582,6 +2657,9 @@ static const struct pid_entry tgid_base_stuff[] = { 
	INF("limits",	  S_IRUGO, proc_pid_limits),

#ifdef CONFIG_SCHED_DEBUG

	REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),

#endif

#ifdef CONFIG_SCHED_AUTOGROUP

	REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),

#endif

	REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),

#ifdef CONFIG_HAVE_ARCH_TRACEHOOK

kernel/sched/auto_group.c

+57 −11
Original line number Diff line number Diff line
@@ -110,9 +110,6 @@ static inline struct autogroup *autogroup_create(void) 


bool task_wants_autogroup(struct task_struct *p, struct task_group *tg)

{

	if (!sysctl_sched_autogroup_enabled)

		return false;



	if (tg != &root_task_group)

		return false;
@@ -146,11 +143,15 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag) 


	p->signal->autogroup = autogroup_kref_get(ag);



	if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))

		goto out;



	t = p;

	do {

		sched_move_task(t);

	} while_each_thread(p, t);



out:

	unlock_task_sighand(p, &flags);

	autogroup_kref_put(prev);

}
@@ -158,11 +159,8 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag) 
/* Allocates GFP_KERNEL, cannot be called under any spinlock */

void sched_autogroup_create_attach(struct task_struct *p)

{

	struct autogroup *ag;

	struct autogroup *ag = autogroup_create();



	if (!sysctl_sched_autogroup_enabled)

		return;

	ag = autogroup_create();

	autogroup_move_group(p, ag);

	/* drop extra reference added by autogroup_create() */

	autogroup_kref_put(ag);
@@ -178,15 +176,11 @@ EXPORT_SYMBOL(sched_autogroup_detach); 


void sched_autogroup_fork(struct signal_struct *sig)

{

	if (!sysctl_sched_autogroup_enabled)

		return;

	sig->autogroup = autogroup_task_get(current);

}



void sched_autogroup_exit(struct signal_struct *sig)

{

	if (!sysctl_sched_autogroup_enabled)

		return;

	autogroup_kref_put(sig->autogroup);

}
@@ -199,6 +193,58 @@ static int __init setup_autogroup(char *str) 


__setup("noautogroup", setup_autogroup);



#ifdef CONFIG_PROC_FS



int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)

{

	static unsigned long next = INITIAL_JIFFIES;

	struct autogroup *ag;

	int err;



	if (nice < -20 || nice > 19)

		return -EINVAL;



	err = security_task_setnice(current, nice);

	if (err)

		return err;



	if (nice < 0 && !can_nice(current, nice))

		return -EPERM;



	/* this is a heavy operation taking global locks.. */

	if (!capable(CAP_SYS_ADMIN) && time_before(jiffies, next))

		return -EAGAIN;



	next = HZ / 10 + jiffies;

	ag = autogroup_task_get(p);



	down_write(&ag->lock);

	err = sched_group_set_shares(ag->tg, prio_to_weight[nice + 20]);

	if (!err)

		ag->nice = nice;

	up_write(&ag->lock);



	autogroup_kref_put(ag);



	return err;

}



void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)

{

	struct autogroup *ag = autogroup_task_get(p);



	if (!task_group_is_autogroup(ag->tg))

		goto out;



	down_read(&ag->lock);

	seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);

	up_read(&ag->lock);



out:

	autogroup_kref_put(ag);

}

#endif /* CONFIG_PROC_FS */



#ifdef CONFIG_SCHED_DEBUG

int autogroup_path(struct task_group *tg, char *buf, int buflen)

{

kernel/sched/auto_group.h

+8 −1
Original line number Diff line number Diff line
@@ -4,6 +4,11 @@ 
#include <linux/rwsem.h>



struct autogroup {

	/*

	 * reference doesn't mean how many thread attach to this

	 * autogroup now. It just stands for the number of task

	 * could use this autogroup.

	 */

	struct kref		kref;

	struct task_group	*tg;

	struct rw_semaphore	lock;
@@ -24,7 +29,9 @@ extern bool task_wants_autogroup(struct task_struct *p, struct task_group *tg); 
static inline struct task_group *

autogroup_task_group(struct task_struct *p, struct task_group *tg)

{

	if (task_wants_autogroup(p, tg))

	int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);



	if (enabled && task_wants_autogroup(p, tg))

		return p->signal->autogroup->tg;



	return tg;

kernel/sysctl.c

+4 −2
Original line number Diff line number Diff line
@@ -367,8 +367,10 @@ static struct ctl_table kern_table[] = { 
		.procname	= "sched_autogroup_enabled",

		.data		= &sysctl_sched_autogroup_enabled,

		.maxlen		= sizeof(unsigned int),

		.mode		= 0444,

		.proc_handler	= proc_dointvec,

		.mode		= 0644,

		.proc_handler	= proc_dointvec_minmax,

		.extra1		= &zero,

		.extra2		= &one,

	},

#endif

#ifdef CONFIG_CFS_BANDWIDTH