Return-path: Received: from mga11.intel.com ([192.55.52.93]:59061 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752145AbaK0KVd (ORCPT ); Thu, 27 Nov 2014 05:21:33 -0500 From: Jukka Rissanen To: linux-wireless@vger.kernel.org Subject: [PATCH v8 2/2] nl80211: Convert sched_scan_req pointer to RCU pointer Date: Thu, 27 Nov 2014 12:21:08 +0200 Message-Id: <1417083668-11958-3-git-send-email-jukka.rissanen@linux.intel.com> (sfid-20141127_112140_121468_F37E5F3F) In-Reply-To: <1417083668-11958-1-git-send-email-jukka.rissanen@linux.intel.com> References: <1417083668-11958-1-git-send-email-jukka.rissanen@linux.intel.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- 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