Revision bb143f814ea488769ca2e79e0b376139cb5f134b authored by Vineet Gupta on 23 February 2016, 06:25:16 UTC, committed by Vineet Gupta on 24 February 2016, 05:37:28 UTC
ARConnect/MCIP Inter-Core-Interrupt module can't send interrupt to local core. So use core intc capability to trigger software interrupt to self, using an unsued IRQ #21. This showed up as csd deadlock with LTP trace_sched on a dual core system. This test acts as scheduler fuzzer, triggering all sorts of schedulting activity. Trouble starts with IPI to self, which doesn't get delivered (effectively lost due to H/w capability), but the msg intended to be sent remain enqueued in per-cpu @ipi_data. All subsequent IPIs to this core from other cores get elided due to the IPI coalescing optimization in ipi_send_msg_one() where a pending msg implies an IPI already sent and assumes other core is yet to ack it. After the elided IPI, other core simply goes into csd_lock_wait() but never comes out as this core never sees the interrupt. Fixes STAR 9001008624 Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> [4.2] Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
1 parent 3e5177c
core.c
/*
* Copyright (C) 2007, 2008, 2009 Siemens AG
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <net/cfg802154.h>
#include <net/rtnetlink.h>
#include "ieee802154.h"
#include "nl802154.h"
#include "sysfs.h"
#include "core.h"
/* name for sysfs, %d is appended */
#define PHY_NAME "phy"
/* RCU-protected (and RTNL for writers) */
LIST_HEAD(cfg802154_rdev_list);
int cfg802154_rdev_list_generation;
static int wpan_phy_match(struct device *dev, const void *data)
{
return !strcmp(dev_name(dev), (const char *)data);
}
struct wpan_phy *wpan_phy_find(const char *str)
{
struct device *dev;
if (WARN_ON(!str))
return NULL;
dev = class_find_device(&wpan_phy_class, NULL, str, wpan_phy_match);
if (!dev)
return NULL;
return container_of(dev, struct wpan_phy, dev);
}
EXPORT_SYMBOL(wpan_phy_find);
struct wpan_phy_iter_data {
int (*fn)(struct wpan_phy *phy, void *data);
void *data;
};
static int wpan_phy_iter(struct device *dev, void *_data)
{
struct wpan_phy_iter_data *wpid = _data;
struct wpan_phy *phy = container_of(dev, struct wpan_phy, dev);
return wpid->fn(phy, wpid->data);
}
int wpan_phy_for_each(int (*fn)(struct wpan_phy *phy, void *data),
void *data)
{
struct wpan_phy_iter_data wpid = {
.fn = fn,
.data = data,
};
return class_for_each_device(&wpan_phy_class, NULL,
&wpid, wpan_phy_iter);
}
EXPORT_SYMBOL(wpan_phy_for_each);
struct cfg802154_registered_device *
cfg802154_rdev_by_wpan_phy_idx(int wpan_phy_idx)
{
struct cfg802154_registered_device *result = NULL, *rdev;
ASSERT_RTNL();
list_for_each_entry(rdev, &cfg802154_rdev_list, list) {
if (rdev->wpan_phy_idx == wpan_phy_idx) {
result = rdev;
break;
}
}
return result;
}
struct wpan_phy *wpan_phy_idx_to_wpan_phy(int wpan_phy_idx)
{
struct cfg802154_registered_device *rdev;
ASSERT_RTNL();
rdev = cfg802154_rdev_by_wpan_phy_idx(wpan_phy_idx);
if (!rdev)
return NULL;
return &rdev->wpan_phy;
}
struct wpan_phy *
wpan_phy_new(const struct cfg802154_ops *ops, size_t priv_size)
{
static atomic_t wpan_phy_counter = ATOMIC_INIT(0);
struct cfg802154_registered_device *rdev;
size_t alloc_size;
alloc_size = sizeof(*rdev) + priv_size;
rdev = kzalloc(alloc_size, GFP_KERNEL);
if (!rdev)
return NULL;
rdev->ops = ops;
rdev->wpan_phy_idx = atomic_inc_return(&wpan_phy_counter);
if (unlikely(rdev->wpan_phy_idx < 0)) {
/* ugh, wrapped! */
atomic_dec(&wpan_phy_counter);
kfree(rdev);
return NULL;
}
/* atomic_inc_return makes it start at 1, make it start at 0 */
rdev->wpan_phy_idx--;
INIT_LIST_HEAD(&rdev->wpan_dev_list);
device_initialize(&rdev->wpan_phy.dev);
dev_set_name(&rdev->wpan_phy.dev, PHY_NAME "%d", rdev->wpan_phy_idx);
rdev->wpan_phy.dev.class = &wpan_phy_class;
rdev->wpan_phy.dev.platform_data = rdev;
init_waitqueue_head(&rdev->dev_wait);
return &rdev->wpan_phy;
}
EXPORT_SYMBOL(wpan_phy_new);
int wpan_phy_register(struct wpan_phy *phy)
{
struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(phy);
int ret;
rtnl_lock();
ret = device_add(&phy->dev);
if (ret) {
rtnl_unlock();
return ret;
}
list_add_rcu(&rdev->list, &cfg802154_rdev_list);
cfg802154_rdev_list_generation++;
/* TODO phy registered lock */
rtnl_unlock();
/* TODO nl802154 phy notify */
return 0;
}
EXPORT_SYMBOL(wpan_phy_register);
void wpan_phy_unregister(struct wpan_phy *phy)
{
struct cfg802154_registered_device *rdev = wpan_phy_to_rdev(phy);
wait_event(rdev->dev_wait, ({
int __count;
rtnl_lock();
__count = rdev->opencount;
rtnl_unlock();
__count == 0; }));
rtnl_lock();
/* TODO nl802154 phy notify */
/* TODO phy registered lock */
WARN_ON(!list_empty(&rdev->wpan_dev_list));
/* First remove the hardware from everywhere, this makes
* it impossible to find from userspace.
*/
list_del_rcu(&rdev->list);
synchronize_rcu();
cfg802154_rdev_list_generation++;
device_del(&phy->dev);
rtnl_unlock();
}
EXPORT_SYMBOL(wpan_phy_unregister);
void wpan_phy_free(struct wpan_phy *phy)
{
put_device(&phy->dev);
}
EXPORT_SYMBOL(wpan_phy_free);
void cfg802154_dev_free(struct cfg802154_registered_device *rdev)
{
kfree(rdev);
}
static void
cfg802154_update_iface_num(struct cfg802154_registered_device *rdev,
int iftype, int num)
{
ASSERT_RTNL();
rdev->num_running_ifaces += num;
}
static int cfg802154_netdev_notifier_call(struct notifier_block *nb,
unsigned long state, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct wpan_dev *wpan_dev = dev->ieee802154_ptr;
struct cfg802154_registered_device *rdev;
if (!wpan_dev)
return NOTIFY_DONE;
rdev = wpan_phy_to_rdev(wpan_dev->wpan_phy);
/* TODO WARN_ON unspec type */
switch (state) {
/* TODO NETDEV_DEVTYPE */
case NETDEV_REGISTER:
dev->features |= NETIF_F_NETNS_LOCAL;
wpan_dev->identifier = ++rdev->wpan_dev_id;
list_add_rcu(&wpan_dev->list, &rdev->wpan_dev_list);
rdev->devlist_generation++;
wpan_dev->netdev = dev;
break;
case NETDEV_DOWN:
cfg802154_update_iface_num(rdev, wpan_dev->iftype, -1);
rdev->opencount--;
wake_up(&rdev->dev_wait);
break;
case NETDEV_UP:
cfg802154_update_iface_num(rdev, wpan_dev->iftype, 1);
rdev->opencount++;
break;
case NETDEV_UNREGISTER:
/* It is possible to get NETDEV_UNREGISTER
* multiple times. To detect that, check
* that the interface is still on the list
* of registered interfaces, and only then
* remove and clean it up.
*/
if (!list_empty(&wpan_dev->list)) {
list_del_rcu(&wpan_dev->list);
rdev->devlist_generation++;
}
/* synchronize (so that we won't find this netdev
* from other code any more) and then clear the list
* head so that the above code can safely check for
* !list_empty() to avoid double-cleanup.
*/
synchronize_rcu();
INIT_LIST_HEAD(&wpan_dev->list);
break;
default:
return NOTIFY_DONE;
}
return NOTIFY_OK;
}
static struct notifier_block cfg802154_netdev_notifier = {
.notifier_call = cfg802154_netdev_notifier_call,
};
static int __init wpan_phy_class_init(void)
{
int rc;
rc = wpan_phy_sysfs_init();
if (rc)
goto err;
rc = register_netdevice_notifier(&cfg802154_netdev_notifier);
if (rc)
goto err_nl;
rc = ieee802154_nl_init();
if (rc)
goto err_notifier;
rc = nl802154_init();
if (rc)
goto err_ieee802154_nl;
return 0;
err_ieee802154_nl:
ieee802154_nl_exit();
err_notifier:
unregister_netdevice_notifier(&cfg802154_netdev_notifier);
err_nl:
wpan_phy_sysfs_exit();
err:
return rc;
}
subsys_initcall(wpan_phy_class_init);
static void __exit wpan_phy_class_exit(void)
{
nl802154_exit();
ieee802154_nl_exit();
unregister_netdevice_notifier(&cfg802154_netdev_notifier);
wpan_phy_sysfs_exit();
}
module_exit(wpan_phy_class_exit);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("IEEE 802.15.4 configuration interface");
MODULE_AUTHOR("Dmitry Eremin-Solenikov");
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