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cfg80211: always check for scan end on P2P device

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If a P2P device wdev is removed while it has a scan, then the
scan completion might crash later as it is already freed by
that time. To avoid the crash always check the scan completion
when the P2P device is being removed for some reason. If the
driver already canceled it, don't want and free it, otherwise
warn and leak it to avoid later crashes.

In order to do this, locking needs to be changed away from the
rdev mutex (which can't always be guaranteed). For now, use
the sched_scan_mtx instead, I'll rename it to just scan_mtx in
a later patch.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Johannes Berg
2013-03-19 15:04:07 +01:00
parent 8b305780ed
commit f9f475292d
6 changed files with 92 additions and 47 deletions
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6
net/wireless/sme.c
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@@ -85,6 +85,7 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev)
ASSERT_RTNL();
ASSERT_RDEV_LOCK(rdev);
ASSERT_WDEV_LOCK(wdev);
lockdep_assert_held(&rdev->sched_scan_mtx);
if (rdev->scan_req)
return -EBUSY;
@@ -320,11 +321,9 @@ void cfg80211_sme_scan_done(struct net_device *dev)
{
struct wireless_dev *wdev = dev->ieee80211_ptr;
mutex_lock(&wiphy_to_dev(wdev->wiphy)->devlist_mtx);
wdev_lock(wdev);
__cfg80211_sme_scan_done(dev);
wdev_unlock(wdev);
mutex_unlock(&wiphy_to_dev(wdev->wiphy)->devlist_mtx);
}
void cfg80211_sme_rx_auth(struct net_device *dev,
@@ -924,9 +923,12 @@ int cfg80211_connect(struct cfg80211_registered_device *rdev,
int err;
mutex_lock(&rdev->devlist_mtx);
/* might request scan - scan_mtx -> wdev_mtx dependency */
mutex_lock(&rdev->sched_scan_mtx);
wdev_lock(dev->ieee80211_ptr);
err = __cfg80211_connect(rdev, dev, connect, connkeys, NULL);
wdev_unlock(dev->ieee80211_ptr);
mutex_unlock(&rdev->sched_scan_mtx);
mutex_unlock(&rdev->devlist_mtx);
return err;