linux/drivers/infiniband/ulp/ipoib/ipoib_netlink.c
Erez Shitrit f47944cc2d IPoIB: Fix deadlock between dev_change_flags() and __ipoib_dev_flush()
When ipoib interface is going down it takes all of its children with
it, under mutex.

For each child, dev_change_flags() is called.  That function calls
ipoib_stop() via the ndo, and causes flush of the workqueue.
Sometimes in the workqueue an __ipoib_dev_flush work() is waiting and
when invoked tries to get the same mutex, which leads to a deadlock,
as seen below.

The solution is to switch to rw-sem instead of mutex.

The deadlock:
[11028.165303]  [<ffffffff812b0977>] ? vgacon_scroll+0x107/0x2e0
[11028.171844]  [<ffffffff814eaac5>] schedule_timeout+0x215/0x2e0
[11028.178465]  [<ffffffff8105a5c3>] ? perf_event_task_sched_out+0x33/0x80
[11028.185962]  [<ffffffff814ea743>] wait_for_common+0x123/0x180
[11028.192491]  [<ffffffff8105fa40>] ? default_wake_function+0x0/0x20
[11028.199504]  [<ffffffff814ea85d>] wait_for_completion+0x1d/0x20
[11028.206224]  [<ffffffff8108b4f1>] flush_cpu_workqueue+0x61/0x90
[11028.212948]  [<ffffffff8108b5a0>] ? wq_barrier_func+0x0/0x20
[11028.219375]  [<ffffffff8108bfc4>] flush_workqueue+0x54/0x80
[11028.225712]  [<ffffffffa05a0576>] ipoib_mcast_stop_thread+0x66/0x90 [ib_ipoib]
[11028.233988]  [<ffffffffa059ccea>] ipoib_ib_dev_down+0x6a/0x100 [ib_ipoib]
[11028.241678]  [<ffffffffa059849a>] ipoib_stop+0x8a/0x140 [ib_ipoib]
[11028.248692]  [<ffffffff8142adf1>] dev_close+0x71/0xc0
[11028.254447]  [<ffffffff8142a631>] dev_change_flags+0xa1/0x1d0
[11028.261062]  [<ffffffffa059851b>] ipoib_stop+0x10b/0x140 [ib_ipoib]
[11028.268172]  [<ffffffff8142adf1>] dev_close+0x71/0xc0
[11028.273922]  [<ffffffff8142a631>] dev_change_flags+0xa1/0x1d0
[11028.280452]  [<ffffffff8148f20b>] devinet_ioctl+0x5eb/0x6a0
[11028.286786]  [<ffffffff814903b8>] inet_ioctl+0x88/0xa0
[11028.292633]  [<ffffffff8141591a>] sock_ioctl+0x7a/0x280
[11028.298576]  [<ffffffff81189012>] vfs_ioctl+0x22/0xa0
[11028.304326]  [<ffffffff81140540>] ? unmap_region+0x110/0x130
[11028.310756]  [<ffffffff811891b4>] do_vfs_ioctl+0x84/0x580
[11028.316897]  [<ffffffff81189731>] sys_ioctl+0x81/0xa0

and

11028.017533]  [<ffffffff8105a5c3>] ? perf_event_task_sched_out+0x33/0x80
[11028.025030]  [<ffffffff8100bb8e>] ? apic_timer_interrupt+0xe/0x20
[11028.031945]  [<ffffffff814eb2ae>] __mutex_lock_slowpath+0x13e/0x180
[11028.039053]  [<ffffffff814eb14b>] mutex_lock+0x2b/0x50
[11028.044910]  [<ffffffffa059f7e7>] __ipoib_ib_dev_flush+0x37/0x210 [ib_ipoib]
[11028.052894]  [<ffffffffa059fa00>] ? ipoib_ib_dev_flush_light+0x0/0x20 [ib_ipoib]
[11028.061363]  [<ffffffffa059fa17>] ipoib_ib_dev_flush_light+0x17/0x20 [ib_ipoib]
[11028.069738]  [<ffffffff8108b120>] worker_thread+0x170/0x2a0
[11028.076068]  [<ffffffff81090990>] ? autoremove_wake_function+0x0/0x40
[11028.083374]  [<ffffffff8108afb0>] ? worker_thread+0x0/0x2a0
[11028.089709]  [<ffffffff81090626>] kthread+0x96/0xa0
[11028.095266]  [<ffffffff8100c0ca>] child_rip+0xa/0x20
[11028.100921]  [<ffffffff81090590>] ? kthread+0x0/0xa0
[11028.106573]  [<ffffffff8100c0c0>] ? child_rip+0x0/0x20
[11028.112423] INFO: task ifconfig:23640 blocked for more than 120 seconds.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
2013-11-08 14:42:49 -08:00

182 lines
4.9 KiB
C

/*
* Copyright (c) 2012 Mellanox Technologies. - All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* OpenIB.org BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - 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.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/netdevice.h>
#include <linux/module.h>
#include <net/rtnetlink.h>
#include "ipoib.h"
static const struct nla_policy ipoib_policy[IFLA_IPOIB_MAX + 1] = {
[IFLA_IPOIB_PKEY] = { .type = NLA_U16 },
[IFLA_IPOIB_MODE] = { .type = NLA_U16 },
[IFLA_IPOIB_UMCAST] = { .type = NLA_U16 },
};
static int ipoib_fill_info(struct sk_buff *skb, const struct net_device *dev)
{
struct ipoib_dev_priv *priv = netdev_priv(dev);
u16 val;
if (nla_put_u16(skb, IFLA_IPOIB_PKEY, priv->pkey))
goto nla_put_failure;
val = test_bit(IPOIB_FLAG_ADMIN_CM, &priv->flags);
if (nla_put_u16(skb, IFLA_IPOIB_MODE, val))
goto nla_put_failure;
val = test_bit(IPOIB_FLAG_UMCAST, &priv->flags);
if (nla_put_u16(skb, IFLA_IPOIB_UMCAST, val))
goto nla_put_failure;
return 0;
nla_put_failure:
return -EMSGSIZE;
}
static int ipoib_changelink(struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
u16 mode, umcast;
int ret = 0;
if (data[IFLA_IPOIB_MODE]) {
mode = nla_get_u16(data[IFLA_IPOIB_MODE]);
if (mode == IPOIB_MODE_DATAGRAM)
ret = ipoib_set_mode(dev, "datagram\n");
else if (mode == IPOIB_MODE_CONNECTED)
ret = ipoib_set_mode(dev, "connected\n");
else
ret = -EINVAL;
if (ret < 0)
goto out_err;
}
if (data[IFLA_IPOIB_UMCAST]) {
umcast = nla_get_u16(data[IFLA_IPOIB_UMCAST]);
ipoib_set_umcast(dev, umcast);
}
out_err:
return ret;
}
static int ipoib_new_child_link(struct net *src_net, struct net_device *dev,
struct nlattr *tb[], struct nlattr *data[])
{
struct net_device *pdev;
struct ipoib_dev_priv *ppriv;
u16 child_pkey;
int err;
if (!tb[IFLA_LINK])
return -EINVAL;
pdev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
if (!pdev)
return -ENODEV;
ppriv = netdev_priv(pdev);
if (test_bit(IPOIB_FLAG_SUBINTERFACE, &ppriv->flags)) {
ipoib_warn(ppriv, "child creation disallowed for child devices\n");
return -EINVAL;
}
if (!data || !data[IFLA_IPOIB_PKEY]) {
ipoib_dbg(ppriv, "no pkey specified, using parent pkey\n");
child_pkey = ppriv->pkey;
} else
child_pkey = nla_get_u16(data[IFLA_IPOIB_PKEY]);
if (child_pkey == 0 || child_pkey == 0x8000)
return -EINVAL;
/*
* Set the full membership bit, so that we join the right
* broadcast group, etc.
*/
child_pkey |= 0x8000;
err = __ipoib_vlan_add(ppriv, netdev_priv(dev), child_pkey, IPOIB_RTNL_CHILD);
if (!err && data)
err = ipoib_changelink(dev, tb, data);
return err;
}
static void ipoib_unregister_child_dev(struct net_device *dev, struct list_head *head)
{
struct ipoib_dev_priv *priv, *ppriv;
priv = netdev_priv(dev);
ppriv = netdev_priv(priv->parent);
down_write(&ppriv->vlan_rwsem);
unregister_netdevice_queue(dev, head);
list_del(&priv->list);
up_write(&ppriv->vlan_rwsem);
}
static size_t ipoib_get_size(const struct net_device *dev)
{
return nla_total_size(2) + /* IFLA_IPOIB_PKEY */
nla_total_size(2) + /* IFLA_IPOIB_MODE */
nla_total_size(2); /* IFLA_IPOIB_UMCAST */
}
static struct rtnl_link_ops ipoib_link_ops __read_mostly = {
.kind = "ipoib",
.maxtype = IFLA_IPOIB_MAX,
.policy = ipoib_policy,
.priv_size = sizeof(struct ipoib_dev_priv),
.setup = ipoib_setup,
.newlink = ipoib_new_child_link,
.changelink = ipoib_changelink,
.dellink = ipoib_unregister_child_dev,
.get_size = ipoib_get_size,
.fill_info = ipoib_fill_info,
};
int __init ipoib_netlink_init(void)
{
return rtnl_link_register(&ipoib_link_ops);
}
void __exit ipoib_netlink_fini(void)
{
rtnl_link_unregister(&ipoib_link_ops);
}
MODULE_ALIAS_RTNL_LINK("ipoib");