linux/drivers/infiniband/ulp/ipoib/ipoib_vlan.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

210 lines
5.2 KiB
C

/*
* Copyright (c) 2004 Topspin Communications. 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/module.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
#include "ipoib.h"
static ssize_t show_parent(struct device *d, struct device_attribute *attr,
char *buf)
{
struct net_device *dev = to_net_dev(d);
struct ipoib_dev_priv *priv = netdev_priv(dev);
return sprintf(buf, "%s\n", priv->parent->name);
}
static DEVICE_ATTR(parent, S_IRUGO, show_parent, NULL);
int __ipoib_vlan_add(struct ipoib_dev_priv *ppriv, struct ipoib_dev_priv *priv,
u16 pkey, int type)
{
int result;
priv->max_ib_mtu = ppriv->max_ib_mtu;
/* MTU will be reset when mcast join happens */
priv->dev->mtu = IPOIB_UD_MTU(priv->max_ib_mtu);
priv->mcast_mtu = priv->admin_mtu = priv->dev->mtu;
set_bit(IPOIB_FLAG_SUBINTERFACE, &priv->flags);
result = ipoib_set_dev_features(priv, ppriv->ca);
if (result)
goto err;
priv->pkey = pkey;
memcpy(priv->dev->dev_addr, ppriv->dev->dev_addr, INFINIBAND_ALEN);
priv->dev->broadcast[8] = pkey >> 8;
priv->dev->broadcast[9] = pkey & 0xff;
result = ipoib_dev_init(priv->dev, ppriv->ca, ppriv->port);
if (result < 0) {
ipoib_warn(ppriv, "failed to initialize subinterface: "
"device %s, port %d",
ppriv->ca->name, ppriv->port);
goto err;
}
result = register_netdevice(priv->dev);
if (result) {
ipoib_warn(priv, "failed to initialize; error %i", result);
goto register_failed;
}
priv->parent = ppriv->dev;
ipoib_create_debug_files(priv->dev);
/* RTNL childs don't need proprietary sysfs entries */
if (type == IPOIB_LEGACY_CHILD) {
if (ipoib_cm_add_mode_attr(priv->dev))
goto sysfs_failed;
if (ipoib_add_pkey_attr(priv->dev))
goto sysfs_failed;
if (ipoib_add_umcast_attr(priv->dev))
goto sysfs_failed;
if (device_create_file(&priv->dev->dev, &dev_attr_parent))
goto sysfs_failed;
}
priv->child_type = type;
priv->dev->iflink = ppriv->dev->ifindex;
list_add_tail(&priv->list, &ppriv->child_intfs);
return 0;
sysfs_failed:
result = -ENOMEM;
ipoib_delete_debug_files(priv->dev);
unregister_netdevice(priv->dev);
register_failed:
ipoib_dev_cleanup(priv->dev);
err:
return result;
}
int ipoib_vlan_add(struct net_device *pdev, unsigned short pkey)
{
struct ipoib_dev_priv *ppriv, *priv;
char intf_name[IFNAMSIZ];
struct ipoib_dev_priv *tpriv;
int result;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
ppriv = netdev_priv(pdev);
snprintf(intf_name, sizeof intf_name, "%s.%04x",
ppriv->dev->name, pkey);
priv = ipoib_intf_alloc(intf_name);
if (!priv)
return -ENOMEM;
if (!rtnl_trylock())
return restart_syscall();
down_write(&ppriv->vlan_rwsem);
/*
* First ensure this isn't a duplicate. We check the parent device and
* then all of the legacy child interfaces to make sure the Pkey
* doesn't match.
*/
if (ppriv->pkey == pkey) {
result = -ENOTUNIQ;
goto out;
}
list_for_each_entry(tpriv, &ppriv->child_intfs, list) {
if (tpriv->pkey == pkey &&
tpriv->child_type == IPOIB_LEGACY_CHILD) {
result = -ENOTUNIQ;
goto out;
}
}
result = __ipoib_vlan_add(ppriv, priv, pkey, IPOIB_LEGACY_CHILD);
out:
up_write(&ppriv->vlan_rwsem);
if (result)
free_netdev(priv->dev);
rtnl_unlock();
return result;
}
int ipoib_vlan_delete(struct net_device *pdev, unsigned short pkey)
{
struct ipoib_dev_priv *ppriv, *priv, *tpriv;
struct net_device *dev = NULL;
if (!capable(CAP_NET_ADMIN))
return -EPERM;
ppriv = netdev_priv(pdev);
if (!rtnl_trylock())
return restart_syscall();
down_write(&ppriv->vlan_rwsem);
list_for_each_entry_safe(priv, tpriv, &ppriv->child_intfs, list) {
if (priv->pkey == pkey &&
priv->child_type == IPOIB_LEGACY_CHILD) {
unregister_netdevice(priv->dev);
list_del(&priv->list);
dev = priv->dev;
break;
}
}
up_write(&ppriv->vlan_rwsem);
rtnl_unlock();
if (dev) {
free_netdev(dev);
return 0;
}
return -ENODEV;
}