/* Function to determine if a thread group is single threaded or not
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * - Derived from security/selinux/hooks.c
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/sched.h>

/*
 * Returns true if the task does not share ->mm with another thread/process.
 */
bool current_is_single_threaded(void)
{
	struct task_struct *task = current;
	struct mm_struct *mm = task->mm;
	struct task_struct *p, *t;
	bool ret;

	if (atomic_read(&task->signal->live) != 1)
		return false;

	if (atomic_read(&mm->mm_users) == 1)
		return true;

	ret = false;
	rcu_read_lock();
	for_each_process(p) {
		if (unlikely(p->flags & PF_KTHREAD))
			continue;
		if (unlikely(p == task->group_leader))
			continue;

		for_each_thread(p, t) {
			if (unlikely(t->mm == mm))
				goto found;
			if (likely(t->mm))
				break;
			/*
			 * t->mm == NULL. Make sure next_thread/next_task
			 * will see other CLONE_VM tasks which might be
			 * forked before exiting.
			 */
			smp_rmb();
		}
	}
	ret = true;
found:
	rcu_read_unlock();

	return ret;
}
-loop-back</option>
<option value='packet-rx-pump-back'>packet-rx-pump-back</option>
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<tr><td class='sub'>net-next plumbings</td><td class='sub right'>Tobias Klauser</td></tr></table>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>perf</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/Documentation?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>Documentation</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/Documentation/perf-config.txt?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>perf-config.txt</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='07cd12945551b63ecb1a349d50a6d69d1d6feb4a'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-26 16:47:28 -0500</td></tr>
<tr><th>committer</th><td>Tejun Heo &lt;tj@kernel.org&gt;</td><td class='right'>2017-01-26 16:47:28 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/Documentation/perf-config.txt?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>07cd12945551b63ecb1a349d50a6d69d1d6feb4a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/perf/Documentation/perf-config.txt?id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>patch</a>)</td></tr>
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<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/Documentation/perf-config.txt?h=nds-private-remove&amp;id=7ce7d89f48834cefece7804d38fc5d85382edf77'>7ce7d89f48834cefece7804d38fc5d85382edf77</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/perf/Documentation/perf-config.txt?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a&amp;id2=7ce7d89f48834cefece7804d38fc5d85382edf77'>diff</a>)</td></tr></table>
<div class='commit-subject'>cgroup: don't online subsystems before cgroup_name/path() are operational</div><div class='commit-msg'>While refactoring cgroup creation, a5bca2152036 ("cgroup: factor out
cgroup_create() out of cgroup_mkdir()") incorrectly onlined subsystems
before the new cgroup is associated with it kernfs_node.  This is fine
for cgroup proper but cgroup_name/path() depend on the associated
kernfs_node and if a subsystem makes the new cgroup_subsys_state
visible, which they're allowed to after onlining, it can lead to NULL
dereference.

The current code performs cgroup creation and subsystem onlining in
cgroup_create() and cgroup_mkdir() makes the cgroup and subsystems
visible afterwards.  There's no reason to online the subsystems early
and we can simply drop cgroup_apply_control_enable() call from
cgroup_create() so that the subsystems are onlined and made visible at
the same time.

Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt;
Reported-by: Konstantin Khlebnikov &lt;khlebnikov@yandex-team.ru&gt;
Fixes: a5bca2152036 ("cgroup: factor out cgroup_create() out of cgroup_mkdir()") 
Cc: stable@vger.kernel.org # v4.6+
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>Diffstat</a> (limited to 'tools/perf/Documentation/perf-config.txt')</div><table summary='diffstat' class='diffstat'>