package/mac80211/patches/100-cfg80211_fix_scan_check_again.patch

   1 Subject: cfg80211: check lost scans later, fix bug
   2
   3 When we lose a scan, cfg80211 tries to clean up after
   4 the driver. However, it currently does this too early,
   5 it does this in GOING_DOWN already instead of DOWN, so
   6 it may happen with mac80211. Besides fixing this, also
   7 make it more robust by leaking the scan request so if
   8 the driver later actually finishes the scan, it won't
   9 crash. Also check in ___cfg80211_scan_done whether a
  10 scan request is still pending and exit if not.
  11
  12 Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
  13 ---
  14  net/wireless/core.c |    4 +++-
  15  net/wireless/core.h |    2 +-
  16  net/wireless/scan.c |   19 ++++++++++++++++---
  17  3 files changed, 20 insertions(+), 5 deletions(-)
  18
  19 --- a/net/wireless/core.c
  20 +++ b/net/wireless/core.c
  21 @@ -664,7 +664,7 @@ static void wdev_cleanup_work(struct wor
  22
  23         if (WARN_ON(rdev->scan_req && rdev->scan_req->dev == wdev->netdev)) {
  24                 rdev->scan_req->aborted = true;
  25 -               ___cfg80211_scan_done(rdev);
  26 +               ___cfg80211_scan_done(rdev, true);
  27         }
  28
  29         cfg80211_unlock_rdev(rdev);
  30 @@ -755,6 +755,8 @@ static int cfg80211_netdev_notifier_call
  31                 default:
  32                         break;
  33                 }
  34 +               break;
  35 +       case NETDEV_DOWN:
  36                 dev_hold(dev);
  37                 schedule_work(&wdev->cleanup_work);
  38                 break;
  39 --- a/net/wireless/core.h
  40 +++ b/net/wireless/core.h
  41 @@ -374,7 +374,7 @@ void cfg80211_sme_scan_done(struct net_d
  42  void cfg80211_sme_rx_auth(struct net_device *dev, const u8 *buf, size_t len);
  43  void cfg80211_sme_disassoc(struct net_device *dev, int idx);
  44  void __cfg80211_scan_done(struct work_struct *wk);
  45 -void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev);
  46 +void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak);
  47  void cfg80211_upload_connect_keys(struct wireless_dev *wdev);
  48
  49  struct ieee80211_channel *
  50 --- a/net/wireless/scan.c
  51 +++ b/net/wireless/scan.c
  52 @@ -18,7 +18,7 @@
  53
  54  #define IEEE80211_SCAN_RESULT_EXPIRE   (15 * HZ)
  55
  56 -void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev)
  57 +void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
  58  {
  59         struct cfg80211_scan_request *request;
  60         struct net_device *dev;
  61 @@ -28,6 +28,9 @@ void ___cfg80211_scan_done(struct cfg802
  62
  63         request = rdev->scan_req;
  64
  65 +       if (!request)
  66 +               return;
  67 +
  68         dev = request->dev;
  69
  70         /*
  71 @@ -53,7 +56,17 @@ void ___cfg80211_scan_done(struct cfg802
  72         dev_put(dev);
  73
  74         rdev->scan_req = NULL;
  75 -       kfree(request);
  76 +
  77 +       /*
  78 +        * OK. If this is invoked with "leak" then we can't
  79 +        * free this ... but we've cleaned it up anyway. The
  80 +        * driver failed to call the scan_done callback, so
  81 +        * all bets are off, it might still be trying to use
  82 +        * the scan request or not ... if it accesses the dev
  83 +        * in there (it shouldn't anyway) then it may crash.
  84 +        */
  85 +       if (!leak)
  86 +               kfree(request);
  87  }
  88
  89  void __cfg80211_scan_done(struct work_struct *wk)
  90 @@ -64,7 +77,7 @@ void __cfg80211_scan_done(struct work_st
  91                             scan_done_wk);
  92
  93         cfg80211_lock_rdev(rdev);
  94 -       ___cfg80211_scan_done(rdev);
  95 +       ___cfg80211_scan_done(rdev, false);
  96         cfg80211_unlock_rdev(rdev);
  97  }
  98