/*
 *	STP SAP demux
 *
 *	Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	version 2 as published by the Free Software Foundation.
 */
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/llc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/llc.h>
#include <net/llc_pdu.h>
#include <net/stp.h>

/* 01:80:c2:00:00:20 - 01:80:c2:00:00:2F */
#define GARP_ADDR_MIN	0x20
#define GARP_ADDR_MAX	0x2F
#define GARP_ADDR_RANGE	(GARP_ADDR_MAX - GARP_ADDR_MIN)

static const struct stp_proto __rcu *garp_protos[GARP_ADDR_RANGE + 1] __read_mostly;
static const struct stp_proto __rcu *stp_proto __read_mostly;

static struct llc_sap *sap __read_mostly;
static unsigned int sap_registered;
static DEFINE_MUTEX(stp_proto_mutex);

/* Called under rcu_read_lock from LLC */
static int stp_pdu_rcv(struct sk_buff *skb, struct net_device *dev,
		       struct packet_type *pt, struct net_device *orig_dev)
{
	const struct ethhdr *eh = eth_hdr(skb);
	const struct llc_pdu_un *pdu = llc_pdu_un_hdr(skb);
	const struct stp_proto *proto;

	if (pdu->ssap != LLC_SAP_BSPAN ||
	    pdu->dsap != LLC_SAP_BSPAN ||
	    pdu->ctrl_1 != LLC_PDU_TYPE_U)
		goto err;

	if (eh->h_dest[5] >= GARP_ADDR_MIN && eh->h_dest[5] <= GARP_ADDR_MAX) {
		proto = rcu_dereference(garp_protos[eh->h_dest[5] -
						    GARP_ADDR_MIN]);
		if (proto &&
		    !ether_addr_equal(eh->h_dest, proto->group_address))
			goto err;
	} else
		proto = rcu_dereference(stp_proto);

	if (!proto)
		goto err;

	proto->rcv(proto, skb, dev);
	return 0;

err:
	kfree_skb(skb);
	return 0;
}

int stp_proto_register(const struct stp_proto *proto)
{
	int err = 0;

	mutex_lock(&stp_proto_mutex);
	if (sap_registered++ == 0) {
		sap = llc_sap_open(LLC_SAP_BSPAN, stp_pdu_rcv);
		if (!sap) {
			err = -ENOMEM;
			goto out;
		}
	}
	if (is_zero_ether_addr(proto->group_address))
		rcu_assign_pointer(stp_proto, proto);
	else
		rcu_assign_pointer(garp_protos[proto->group_address[5] -
					       GARP_ADDR_MIN], proto);
out:
	mutex_unlock(&stp_proto_mutex);
	return err;
}
EXPORT_SYMBOL_GPL(stp_proto_register);

void stp_proto_unregister(const struct stp_proto *proto)
{
	mutex_lock(&stp_proto_mutex);
	if (is_zero_ether_addr(proto->group_address))
		RCU_INIT_POINTER(stp_proto, NULL);
	else
		RCU_INIT_POINTER(garp_protos[proto->group_address[5] -
					       GARP_ADDR_MIN], NULL);
	synchronize_rcu();

	if (--sap_registered == 0)
		llc_sap_put(sap);
	mutex_unlock(&stp_proto_mutex);
}
EXPORT_SYMBOL_GPL(stp_proto_unregister);

MODULE_LICENSE("GPL");
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/tree/?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>root</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>arch</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch/microblaze?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>microblaze</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch/microblaze/include?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>include</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch/microblaze/include/uapi?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>uapi</a>/<a href='/cgit.cgi/linux/net-next.git/tree/tools/arch/microblaze/include/uapi/asm?id=e387dc122fc7c70c2a5df2567f4e2d1114f5a5da'>asm</a></div><div class='content'><table summary='tree listing' class='list'>
<tr class='nohover'><th class='left'>Mode</th><th class='left'>Name</th><th class='right'>Size</th><th/></tr>
n' 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/sound/soc/sirf/sirf-usp.c?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>07cd12945551b63ecb1a349d50a6d69d1d6feb4a</a> (<a href='/cgit.cgi/linux/net-next.git/patch/sound/soc/sirf/sirf-usp.c?id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>75f65eba7eac9277971082a2d5a4cf1370562c0c</a> /<a href='/cgit.cgi/linux/net-next.git/tree/sound/soc/sirf/sirf-usp.c?h=nds-private-remove&amp;id=07cd12945551b63ecb1a349d50a6d69d1d6feb4a'>sound/soc/sirf/sirf-usp.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/sound/soc/sirf/sirf-usp.c?h=nds-private-remove&amp;id=7ce7d89f48834cefece7804d38fc5d85382edf77'>7ce7d89f48834cefece7804d38fc5d85382edf77</a> (<a href='/cgit.cgi/linux/net-next.git/diff/sound/soc/sirf/sirf-usp.c?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 'sound/soc/sirf/sirf-usp.c')</div><table summary='diffstat' class='diffstat'>