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authorJohannes Berg <johannes.berg@intel.com>2013-03-25 11:51:14 +0100
committerJohannes Berg <johannes.berg@intel.com>2013-03-25 13:50:33 +0100
commit3fbd45ca8d1c98f3c2582ef8bc70ade42f70947b (patch)
treee19f4ad8aeda39090f26643c2063fc1050300391 /net/mac80211/offchannel.c
parent370bd005937c0e00f9104a602f9fe1dd6b21b54b (diff)
downloadlinux-stericsson-3fbd45ca8d1c98f3c2582ef8bc70ade42f70947b.tar.gz
mac80211: fix remain-on-channel cancel crash
If a ROC item is canceled just as it expires, the work struct may be scheduled while it is running (and waiting for the mutex). This results in it being run after being freed, which obviously crashes. To fix this don't free it when aborting is requested but instead mark it as "to be freed", which makes the work a no-op and allows freeing it outside. Cc: stable@vger.kernel.org [3.6+] Reported-by: Jouni Malinen <j@w1.fi> Tested-by: Jouni Malinen <j@w1.fi> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/offchannel.c')
-rw-r--r--net/mac80211/offchannel.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index cc79b4a2e821..430bd254e496 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -297,10 +297,13 @@ void ieee80211_start_next_roc(struct ieee80211_local *local)
}
}
-void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
+void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free)
{
struct ieee80211_roc_work *dep, *tmp;
+ if (WARN_ON(roc->to_be_freed))
+ return;
+
/* was never transmitted */
if (roc->frame) {
cfg80211_mgmt_tx_status(&roc->sdata->wdev,
@@ -316,9 +319,12 @@ void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc)
GFP_KERNEL);
list_for_each_entry_safe(dep, tmp, &roc->dependents, list)
- ieee80211_roc_notify_destroy(dep);
+ ieee80211_roc_notify_destroy(dep, true);
- kfree(roc);
+ if (free)
+ kfree(roc);
+ else
+ roc->to_be_freed = true;
}
void ieee80211_sw_roc_work(struct work_struct *work)
@@ -331,6 +337,9 @@ void ieee80211_sw_roc_work(struct work_struct *work)
mutex_lock(&local->mtx);
+ if (roc->to_be_freed)
+ goto out_unlock;
+
if (roc->abort)
goto finish;
@@ -370,7 +379,7 @@ void ieee80211_sw_roc_work(struct work_struct *work)
finish:
list_del(&roc->list);
started = roc->started;
- ieee80211_roc_notify_destroy(roc);
+ ieee80211_roc_notify_destroy(roc, !roc->abort);
if (started) {
drv_flush(local, false);
@@ -410,7 +419,7 @@ static void ieee80211_hw_roc_done(struct work_struct *work)
list_del(&roc->list);
- ieee80211_roc_notify_destroy(roc);
+ ieee80211_roc_notify_destroy(roc, true);
/* if there's another roc, start it now */
ieee80211_start_next_roc(local);
@@ -460,12 +469,14 @@ void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata)
list_for_each_entry_safe(roc, tmp, &tmp_list, list) {
if (local->ops->remain_on_channel) {
list_del(&roc->list);
- ieee80211_roc_notify_destroy(roc);
+ ieee80211_roc_notify_destroy(roc, true);
} else {
ieee80211_queue_delayed_work(&local->hw, &roc->work, 0);
/* work will clean up etc */
flush_delayed_work(&roc->work);
+ WARN_ON(!roc->to_be_freed);
+ kfree(roc);
}
}