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| author | Soumik Das <soumik.das@stericsson.com> | 2012-05-20 15:31:13 +0530 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2012-05-25 11:16:16 -0400 |
| commit | 992e68bf2eb9f3319f098560b8d4a03aa52fd7b8 (patch) | |
| tree | 4def5ed9c6845d2a9f48f7f99a429fc89be79b9b /net | |
| parent | edb9bc9a1e08f54adfdb4f4d31bca5a15aeb8ef0 (diff) | |
| download | linux-992e68bf2eb9f3319f098560b8d4a03aa52fd7b8.tar.gz linux-992e68bf2eb9f3319f098560b8d4a03aa52fd7b8.tar.bz2 linux-992e68bf2eb9f3319f098560b8d4a03aa52fd7b8.zip | |
mac80211: Fix race in checking AP status by sending null frame
mac80211 tries to verify the existence of the current AP by
probing or sending a NULL frame in function
ieee80211_mgd_probe_ap_send. It 1st sends a null frame to the AP,
increments probe_send_count and waits for the ACK to the NULL
frame for a finite duration of time. At times, it happens that by
the time mac80211 gets to increment probe_send_count, the ACK for
the NULL frame transmitted has already been processed. This leads
to a race condition where mac80211 times out waiting for the ACK
for the NULL frame causing unnecessary disconnection with the AP.
Signed-off-by: Soumik Das <soumik.das@stericsson.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/mac80211/mlme.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index b3b3c264ff66..04c306308987 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -1522,6 +1522,8 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata) * anymore. The timeout will be reset if the frame is ACKed by * the AP. */ + ifmgd->probe_send_count++; + if (sdata->local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) { ifmgd->nullfunc_failed = false; ieee80211_send_nullfunc(sdata->local, sdata, 0); @@ -1538,7 +1540,6 @@ static void ieee80211_mgd_probe_ap_send(struct ieee80211_sub_if_data *sdata) 0, (u32) -1, true, false); } - ifmgd->probe_send_count++; ifmgd->probe_timeout = jiffies + msecs_to_jiffies(probe_wait_ms); run_again(ifmgd, ifmgd->probe_timeout); if (sdata->local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) |