Because of possible races when accessing sched_scan_req pointer in
rdev, the sched_scan_req is converted to RCU pointer.
Signed-off-by: Jukka Rissanen <jukka.rissa...@linux.intel.com>
---
include/net/cfg80211.h | 1 +
net/wireless/core.c | 10 +++++++---
net/wireless/core.h | 2 +-
net/wireless/nl80211.c | 27 ++++++++++++++++-----------
net/wireless/scan.c | 20 +++++++++++++++-----
5 files changed, 40 insertions(+), 20 deletions(-)
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 5806c75..0e540fc 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1538,6 +1538,7 @@ struct cfg80211_sched_scan_request {
struct net_device *dev;
unsigned long scan_start;
u32 owner_nlportid;
+ struct rcu_head rcu_head;
/* keep last */
struct ieee80211_channel *channels[0];
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 8236e2d..b612b71 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -860,6 +860,7 @@ void __cfg80211_leave(struct cfg80211_registered_device
*rdev,
struct wireless_dev *wdev)
{
struct net_device *dev = wdev->netdev;
+ struct cfg80211_sched_scan_request *sched_scan_req;
ASSERT_RTNL();
ASSERT_WDEV_LOCK(wdev);
@@ -870,7 +871,8 @@ void __cfg80211_leave(struct cfg80211_registered_device
*rdev,
break;
case NL80211_IFTYPE_P2P_CLIENT:
case NL80211_IFTYPE_STATION:
- if (rdev->sched_scan_req && dev == rdev->sched_scan_req->dev)
+ sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
+ if (sched_scan_req && dev == sched_scan_req->dev)
__cfg80211_stop_sched_scan(rdev, false);
#ifdef CONFIG_CFG80211_WEXT
@@ -945,6 +947,7 @@ static int cfg80211_netdev_notifier_call(struct
notifier_block *nb,
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev;
+ struct cfg80211_sched_scan_request *sched_scan_req;
if (!wdev)
return NOTIFY_DONE;
@@ -1009,8 +1012,9 @@ static int cfg80211_netdev_notifier_call(struct
notifier_block *nb,
___cfg80211_scan_done(rdev, false);
}
- if (WARN_ON(rdev->sched_scan_req &&
- rdev->sched_scan_req->dev == wdev->netdev)) {
+ sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
+ if (WARN_ON(sched_scan_req &&
+ sched_scan_req->dev == wdev->netdev)) {
__cfg80211_stop_sched_scan(rdev, false);
}
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 5327375..4e3630b 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -63,7 +63,7 @@ struct cfg80211_registered_device {
u32 bss_generation;
struct cfg80211_scan_request *scan_req; /* protected by RTNL */
struct sk_buff *scan_msg;
- struct cfg80211_sched_scan_request *sched_scan_req;
+ struct cfg80211_sched_scan_request __rcu *sched_scan_req;
unsigned long suspend_at;
struct work_struct scan_done_wk;
struct work_struct sched_scan_results_wk;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index a5cc4d6..6cdb2ff 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6068,6 +6068,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
struct cfg80211_registered_device *rdev = info->user_ptr[0];
struct net_device *dev = info->user_ptr[1];
struct wireless_dev *wdev = dev->ieee80211_ptr;
+ struct cfg80211_sched_scan_request *sched_scan_req;
int err;
if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
@@ -6077,30 +6078,34 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
if (rdev->sched_scan_req)
return -EINPROGRESS;
- rdev->sched_scan_req = nl80211_parse_sched_scan(&rdev->wiphy, wdev,
- info->attrs);
- err = PTR_ERR_OR_ZERO(rdev->sched_scan_req);
+ sched_scan_req = nl80211_parse_sched_scan(&rdev->wiphy, wdev,
+ info->attrs);
+
+ err = PTR_ERR_OR_ZERO(sched_scan_req);
if (err)
goto out_err;
- err = rdev_sched_scan_start(rdev, dev, rdev->sched_scan_req);
+ rcu_assign_pointer(rdev->sched_scan_req, sched_scan_req);
+
+ err = rdev_sched_scan_start(rdev, dev, sched_scan_req);
if (err)
goto out_free;
- rdev->sched_scan_req->dev = dev;
- rdev->sched_scan_req->wiphy = &rdev->wiphy;
-
if (info->attrs[NL80211_ATTR_SOCKET_OWNER])
- rdev->sched_scan_req->owner_nlportid = info->snd_portid;
+ rtnl_dereference(rdev->sched_scan_req)->owner_nlportid =
+ info->snd_portid;
+
+ rtnl_dereference(rdev->sched_scan_req)->dev = dev;
+ rtnl_dereference(rdev->sched_scan_req)->wiphy = &rdev->wiphy;
nl80211_send_sched_scan(rdev, dev,
NL80211_CMD_START_SCHED_SCAN);
return 0;
out_free:
- kfree(rdev->sched_scan_req);
+ kfree_rcu(sched_scan_req, rcu_head);
+ rcu_assign_pointer(rdev->sched_scan_req, NULL);
out_err:
- rdev->sched_scan_req = NULL;
return err;
}
@@ -12476,7 +12481,7 @@ static int nl80211_netlink_notify(struct notifier_block
* nb,
bool schedule_destroy_work = false;
bool schedule_scan_stop = false;
struct cfg80211_sched_scan_request *sched_scan_req =
- rdev->sched_scan_req;
+ rcu_dereference(rdev->sched_scan_req);
if (sched_scan_req && notify->portid &&
sched_scan_req->owner_nlportid == notify->portid)
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index bda39f1..c508d30 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -257,7 +257,7 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
rtnl_lock();
- request = rdev->sched_scan_req;
+ request = rtnl_dereference(rdev->sched_scan_req);
/* we don't have sched_scan_req anymore if the scan is stopping */
if (request) {
@@ -277,9 +277,16 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
void cfg80211_sched_scan_results(struct wiphy *wiphy)
{
+ struct cfg80211_sched_scan_request *sched_scan_req;
+
trace_cfg80211_sched_scan_results(wiphy);
/* ignore if we're not scanning */
- if (wiphy_to_rdev(wiphy)->sched_scan_req)
+
+ rcu_read_lock();
+ sched_scan_req = rcu_dereference(wiphy_to_rdev(wiphy)->sched_scan_req);
+ rcu_read_unlock();
+
+ if (sched_scan_req)
queue_work(cfg80211_wq,
&wiphy_to_rdev(wiphy)->sched_scan_results_wk);
}
@@ -308,6 +315,7 @@ EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
bool driver_initiated)
{
+ struct cfg80211_sched_scan_request *sched_scan_req;
struct net_device *dev;
ASSERT_RTNL();
@@ -315,7 +323,8 @@ int __cfg80211_stop_sched_scan(struct
cfg80211_registered_device *rdev,
if (!rdev->sched_scan_req)
return -ENOENT;
- dev = rdev->sched_scan_req->dev;
+ sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
+ dev = sched_scan_req->dev;
if (!driver_initiated) {
int err = rdev_sched_scan_stop(rdev, dev);
@@ -325,8 +334,9 @@ int __cfg80211_stop_sched_scan(struct
cfg80211_registered_device *rdev,
nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
- kfree(rdev->sched_scan_req);
- rdev->sched_scan_req = NULL;
+ kfree_rcu(sched_scan_req, rcu_head);
+
+ rcu_assign_pointer(rdev->sched_scan_req, NULL);
return 0;
}
--
1.8.3.1
--
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