linux/net/tipc/eth_media.c
Ying Xue 4225a398c1 tipc: fix lockdep warning during bearer initialization
When the lockdep validator is enabled, it will report the below
warning when we enable a TIPC bearer:

[ INFO: possible irq lock inversion dependency detected ]
---------------------------------------------------------
Possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(ptype_lock);
                                local_irq_disable();
                                lock(tipc_net_lock);
                                lock(ptype_lock);
   <Interrupt>
   lock(tipc_net_lock);

  *** DEADLOCK ***

the shortest dependencies between 2nd lock and 1st lock:
  -> (ptype_lock){+.+...} ops: 10 {
[...]
SOFTIRQ-ON-W at:
                      [<c1089418>] __lock_acquire+0x528/0x13e0
                      [<c108a360>] lock_acquire+0x90/0x100
                      [<c1553c38>] _raw_spin_lock+0x38/0x50
                      [<c14651ca>] dev_add_pack+0x3a/0x60
                      [<c182da75>] arp_init+0x1a/0x48
                      [<c182dce5>] inet_init+0x181/0x27e
                      [<c1001114>] do_one_initcall+0x34/0x170
                      [<c17f7329>] kernel_init+0x110/0x1b2
                      [<c155b6a2>] kernel_thread_helper+0x6/0x10
[...]
   ... key      at: [<c17e4b10>] ptype_lock+0x10/0x20
   ... acquired at:
    [<c108a360>] lock_acquire+0x90/0x100
    [<c1553c38>] _raw_spin_lock+0x38/0x50
    [<c14651ca>] dev_add_pack+0x3a/0x60
    [<c8bc18d2>] enable_bearer+0xf2/0x140 [tipc]
    [<c8bb283a>] tipc_enable_bearer+0x1ba/0x450 [tipc]
    [<c8bb3a04>] tipc_cfg_do_cmd+0x5c4/0x830 [tipc]
    [<c8bbc032>] handle_cmd+0x42/0xd0 [tipc]
    [<c148e802>] genl_rcv_msg+0x232/0x280
    [<c148d3f6>] netlink_rcv_skb+0x86/0xb0
    [<c148e5bc>] genl_rcv+0x1c/0x30
    [<c148d144>] netlink_unicast+0x174/0x1f0
    [<c148ddab>] netlink_sendmsg+0x1eb/0x2d0
    [<c1456bc1>] sock_aio_write+0x161/0x170
    [<c1135a7c>] do_sync_write+0xac/0xf0
    [<c11360f6>] vfs_write+0x156/0x170
    [<c11361e2>] sys_write+0x42/0x70
    [<c155b0df>] sysenter_do_call+0x12/0x38
[...]
}
  -> (tipc_net_lock){+..-..} ops: 4 {
[...]
    IN-SOFTIRQ-R at:
                     [<c108953a>] __lock_acquire+0x64a/0x13e0
                     [<c108a360>] lock_acquire+0x90/0x100
                     [<c15541cd>] _raw_read_lock_bh+0x3d/0x50
                     [<c8bb874d>] tipc_recv_msg+0x1d/0x830 [tipc]
                     [<c8bc195f>] recv_msg+0x3f/0x50 [tipc]
                     [<c146a5fa>] __netif_receive_skb+0x22a/0x590
                     [<c146ab0b>] netif_receive_skb+0x2b/0xf0
                     [<c13c43d2>] pcnet32_poll+0x292/0x780
                     [<c146b00a>] net_rx_action+0xfa/0x1e0
                     [<c103a4be>] __do_softirq+0xae/0x1e0
[...]
}

>From the log, we can see three different call chains between
CPU0 and CPU1:

Time 0 on CPU0:

  kernel_init()->inet_init()->dev_add_pack()

At time 0, the ptype_lock is held by CPU0 in dev_add_pack();

Time 1 on CPU1:

  tipc_enable_bearer()->enable_bearer()->dev_add_pack()

At time 1, tipc_enable_bearer() first holds tipc_net_lock, and then
wants to take ptype_lock to register TIPC protocol handler into the
networking stack.  But the ptype_lock has been taken by dev_add_pack()
on CPU0, so at this time the dev_add_pack() running on CPU1 has to be
busy looping.

Time 2 on CPU0:

  netif_receive_skb()->recv_msg()->tipc_recv_msg()

At time 2, an incoming TIPC packet arrives at CPU0, hence
tipc_recv_msg() will be invoked. In tipc_recv_msg(), it first wants
to hold tipc_net_lock.  At the moment, below scenario happens:

On CPU0, below is our sequence of taking locks:

  lock(ptype_lock)->lock(tipc_net_lock)

On CPU1, our sequence of taking locks looks like:

  lock(tipc_net_lock)->lock(ptype_lock)

Obviously deadlock may happen in this case.

But please note the deadlock possibly doesn't occur at all when the
first TIPC bearer is enabled.  Before enable_bearer() -- running on
CPU1 does not hold ptype_lock, so the TIPC receive handler (i.e.
recv_msg()) is not registered successfully via dev_add_pack(), so
the tipc_recv_msg() cannot be called by recv_msg() even if a TIPC
message comes to CPU0. But when the second TIPC bearer is
registered, the deadlock can perhaps really happen.

To fix it, we will push the work of registering TIPC protocol
handler into workqueue context. After the change, both paths taking
ptype_lock are always in process contexts, thus, the deadlock should
never occur.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-08-20 02:26:30 -07:00

401 lines
11 KiB
C

/*
* net/tipc/eth_media.c: Ethernet bearer support for TIPC
*
* Copyright (c) 2001-2007, Ericsson AB
* Copyright (c) 2005-2008, 2011, Wind River Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the names of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "core.h"
#include "bearer.h"
#define MAX_ETH_BEARERS MAX_BEARERS
#define ETH_ADDR_OFFSET 4 /* message header offset of MAC address */
/**
* struct eth_bearer - Ethernet bearer data structure
* @bearer: ptr to associated "generic" bearer structure
* @dev: ptr to associated Ethernet network device
* @tipc_packet_type: used in binding TIPC to Ethernet driver
* @setup: work item used when enabling bearer
* @cleanup: work item used when disabling bearer
*/
struct eth_bearer {
struct tipc_bearer *bearer;
struct net_device *dev;
struct packet_type tipc_packet_type;
struct work_struct setup;
struct work_struct cleanup;
};
static struct tipc_media eth_media_info;
static struct eth_bearer eth_bearers[MAX_ETH_BEARERS];
static int eth_started;
static int recv_notification(struct notifier_block *nb, unsigned long evt,
void *dv);
/*
* Network device notifier info
*/
static struct notifier_block notifier = {
.notifier_call = recv_notification,
.priority = 0
};
/**
* eth_media_addr_set - initialize Ethernet media address structure
*
* Media-dependent "value" field stores MAC address in first 6 bytes
* and zeroes out the remaining bytes.
*/
static void eth_media_addr_set(struct tipc_media_addr *a, char *mac)
{
memcpy(a->value, mac, ETH_ALEN);
memset(a->value + ETH_ALEN, 0, sizeof(a->value) - ETH_ALEN);
a->media_id = TIPC_MEDIA_TYPE_ETH;
a->broadcast = !memcmp(mac, eth_media_info.bcast_addr.value, ETH_ALEN);
}
/**
* send_msg - send a TIPC message out over an Ethernet interface
*/
static int send_msg(struct sk_buff *buf, struct tipc_bearer *tb_ptr,
struct tipc_media_addr *dest)
{
struct sk_buff *clone;
struct net_device *dev;
int delta;
clone = skb_clone(buf, GFP_ATOMIC);
if (!clone)
return 0;
dev = ((struct eth_bearer *)(tb_ptr->usr_handle))->dev;
delta = dev->hard_header_len - skb_headroom(buf);
if ((delta > 0) &&
pskb_expand_head(clone, SKB_DATA_ALIGN(delta), 0, GFP_ATOMIC)) {
kfree_skb(clone);
return 0;
}
skb_reset_network_header(clone);
clone->dev = dev;
dev_hard_header(clone, dev, ETH_P_TIPC, dest->value,
dev->dev_addr, clone->len);
dev_queue_xmit(clone);
return 0;
}
/**
* recv_msg - handle incoming TIPC message from an Ethernet interface
*
* Accept only packets explicitly sent to this node, or broadcast packets;
* ignores packets sent using Ethernet multicast, and traffic sent to other
* nodes (which can happen if interface is running in promiscuous mode).
*/
static int recv_msg(struct sk_buff *buf, struct net_device *dev,
struct packet_type *pt, struct net_device *orig_dev)
{
struct eth_bearer *eb_ptr = (struct eth_bearer *)pt->af_packet_priv;
if (!net_eq(dev_net(dev), &init_net)) {
kfree_skb(buf);
return 0;
}
if (likely(eb_ptr->bearer)) {
if (likely(buf->pkt_type <= PACKET_BROADCAST)) {
buf->next = NULL;
tipc_recv_msg(buf, eb_ptr->bearer);
return 0;
}
}
kfree_skb(buf);
return 0;
}
/**
* setup_bearer - setup association between Ethernet bearer and interface
*/
static void setup_bearer(struct work_struct *work)
{
struct eth_bearer *eb_ptr =
container_of(work, struct eth_bearer, setup);
dev_add_pack(&eb_ptr->tipc_packet_type);
}
/**
* enable_bearer - attach TIPC bearer to an Ethernet interface
*/
static int enable_bearer(struct tipc_bearer *tb_ptr)
{
struct net_device *dev = NULL;
struct net_device *pdev = NULL;
struct eth_bearer *eb_ptr = &eth_bearers[0];
struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
char *driver_name = strchr((const char *)tb_ptr->name, ':') + 1;
int pending_dev = 0;
/* Find unused Ethernet bearer structure */
while (eb_ptr->dev) {
if (!eb_ptr->bearer)
pending_dev++;
if (++eb_ptr == stop)
return pending_dev ? -EAGAIN : -EDQUOT;
}
/* Find device with specified name */
read_lock(&dev_base_lock);
for_each_netdev(&init_net, pdev) {
if (!strncmp(pdev->name, driver_name, IFNAMSIZ)) {
dev = pdev;
dev_hold(dev);
break;
}
}
read_unlock(&dev_base_lock);
if (!dev)
return -ENODEV;
/* Create Ethernet bearer for device */
eb_ptr->dev = dev;
eb_ptr->tipc_packet_type.type = htons(ETH_P_TIPC);
eb_ptr->tipc_packet_type.dev = dev;
eb_ptr->tipc_packet_type.func = recv_msg;
eb_ptr->tipc_packet_type.af_packet_priv = eb_ptr;
INIT_LIST_HEAD(&(eb_ptr->tipc_packet_type.list));
INIT_WORK(&eb_ptr->setup, setup_bearer);
schedule_work(&eb_ptr->setup);
/* Associate TIPC bearer with Ethernet bearer */
eb_ptr->bearer = tb_ptr;
tb_ptr->usr_handle = (void *)eb_ptr;
tb_ptr->mtu = dev->mtu;
tb_ptr->blocked = 0;
eth_media_addr_set(&tb_ptr->addr, (char *)dev->dev_addr);
return 0;
}
/**
* cleanup_bearer - break association between Ethernet bearer and interface
*
* This routine must be invoked from a work queue because it can sleep.
*/
static void cleanup_bearer(struct work_struct *work)
{
struct eth_bearer *eb_ptr =
container_of(work, struct eth_bearer, cleanup);
dev_remove_pack(&eb_ptr->tipc_packet_type);
dev_put(eb_ptr->dev);
eb_ptr->dev = NULL;
}
/**
* disable_bearer - detach TIPC bearer from an Ethernet interface
*
* Mark Ethernet bearer as inactive so that incoming buffers are thrown away,
* then get worker thread to complete bearer cleanup. (Can't do cleanup
* here because cleanup code needs to sleep and caller holds spinlocks.)
*/
static void disable_bearer(struct tipc_bearer *tb_ptr)
{
struct eth_bearer *eb_ptr = (struct eth_bearer *)tb_ptr->usr_handle;
eb_ptr->bearer = NULL;
INIT_WORK(&eb_ptr->cleanup, cleanup_bearer);
schedule_work(&eb_ptr->cleanup);
}
/**
* recv_notification - handle device updates from OS
*
* Change the state of the Ethernet bearer (if any) associated with the
* specified device.
*/
static int recv_notification(struct notifier_block *nb, unsigned long evt,
void *dv)
{
struct net_device *dev = (struct net_device *)dv;
struct eth_bearer *eb_ptr = &eth_bearers[0];
struct eth_bearer *stop = &eth_bearers[MAX_ETH_BEARERS];
if (!net_eq(dev_net(dev), &init_net))
return NOTIFY_DONE;
while ((eb_ptr->dev != dev)) {
if (++eb_ptr == stop)
return NOTIFY_DONE; /* couldn't find device */
}
if (!eb_ptr->bearer)
return NOTIFY_DONE; /* bearer had been disabled */
eb_ptr->bearer->mtu = dev->mtu;
switch (evt) {
case NETDEV_CHANGE:
if (netif_carrier_ok(dev))
tipc_continue(eb_ptr->bearer);
else
tipc_block_bearer(eb_ptr->bearer->name);
break;
case NETDEV_UP:
tipc_continue(eb_ptr->bearer);
break;
case NETDEV_DOWN:
tipc_block_bearer(eb_ptr->bearer->name);
break;
case NETDEV_CHANGEMTU:
case NETDEV_CHANGEADDR:
tipc_block_bearer(eb_ptr->bearer->name);
tipc_continue(eb_ptr->bearer);
break;
case NETDEV_UNREGISTER:
case NETDEV_CHANGENAME:
tipc_disable_bearer(eb_ptr->bearer->name);
break;
}
return NOTIFY_OK;
}
/**
* eth_addr2str - convert Ethernet address to string
*/
static int eth_addr2str(struct tipc_media_addr *a, char *str_buf, int str_size)
{
if (str_size < 18) /* 18 = strlen("aa:bb:cc:dd:ee:ff\0") */
return 1;
sprintf(str_buf, "%pM", a->value);
return 0;
}
/**
* eth_str2addr - convert string to Ethernet address
*/
static int eth_str2addr(struct tipc_media_addr *a, char *str_buf)
{
char mac[ETH_ALEN];
int r;
r = sscanf(str_buf, "%02x:%02x:%02x:%02x:%02x:%02x",
(u32 *)&mac[0], (u32 *)&mac[1], (u32 *)&mac[2],
(u32 *)&mac[3], (u32 *)&mac[4], (u32 *)&mac[5]);
if (r != ETH_ALEN)
return 1;
eth_media_addr_set(a, mac);
return 0;
}
/**
* eth_str2addr - convert Ethernet address format to message header format
*/
static int eth_addr2msg(struct tipc_media_addr *a, char *msg_area)
{
memset(msg_area, 0, TIPC_MEDIA_ADDR_SIZE);
msg_area[TIPC_MEDIA_TYPE_OFFSET] = TIPC_MEDIA_TYPE_ETH;
memcpy(msg_area + ETH_ADDR_OFFSET, a->value, ETH_ALEN);
return 0;
}
/**
* eth_str2addr - convert message header address format to Ethernet format
*/
static int eth_msg2addr(struct tipc_media_addr *a, char *msg_area)
{
if (msg_area[TIPC_MEDIA_TYPE_OFFSET] != TIPC_MEDIA_TYPE_ETH)
return 1;
eth_media_addr_set(a, msg_area + ETH_ADDR_OFFSET);
return 0;
}
/*
* Ethernet media registration info
*/
static struct tipc_media eth_media_info = {
.send_msg = send_msg,
.enable_bearer = enable_bearer,
.disable_bearer = disable_bearer,
.addr2str = eth_addr2str,
.str2addr = eth_str2addr,
.addr2msg = eth_addr2msg,
.msg2addr = eth_msg2addr,
.bcast_addr = { { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff },
TIPC_MEDIA_TYPE_ETH, 1 },
.priority = TIPC_DEF_LINK_PRI,
.tolerance = TIPC_DEF_LINK_TOL,
.window = TIPC_DEF_LINK_WIN,
.type_id = TIPC_MEDIA_TYPE_ETH,
.name = "eth"
};
/**
* tipc_eth_media_start - activate Ethernet bearer support
*
* Register Ethernet media type with TIPC bearer code. Also register
* with OS for notifications about device state changes.
*/
int tipc_eth_media_start(void)
{
int res;
if (eth_started)
return -EINVAL;
res = tipc_register_media(&eth_media_info);
if (res)
return res;
res = register_netdevice_notifier(&notifier);
if (!res)
eth_started = 1;
return res;
}
/**
* tipc_eth_media_stop - deactivate Ethernet bearer support
*/
void tipc_eth_media_stop(void)
{
if (!eth_started)
return;
flush_scheduled_work();
unregister_netdevice_notifier(&notifier);
eth_started = 0;
}