diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2023-06-18 21:49:58 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2023-06-19 14:12:43 +0300 |
| commit | 92bf4dd35801b4e3e73d3cc4beb5c929f75e0da6 (patch) | |
| tree | 26a5a26c5b666ab680a78c58e1f11208112ea661 /net/mac80211/agg-tx.c | |
| parent | 6f2db6588b8189caeeb8249727b8344eba991250 (diff) | |
| download | linux-92bf4dd35801b4e3e73d3cc4beb5c929f75e0da6.tar.xz | |
wifi: mac80211: agg-tx: prevent start/stop race
There were crashes reported in this code, and the timer_shutdown()
warning in one of the previous patches indicates that the timeout
timer for the AP response (addba_resp_timer) is still armed while
we're stopping the aggregation session.
After a very long deliberation of the code, so far the only way I
could find that might cause this would be the following sequence:
- session start requested
- session start indicated to driver, but driver returns
IEEE80211_AMPDU_TX_START_DELAY_ADDBA
- session stop requested, sets HT_AGG_STATE_WANT_STOP
- session stop worker runs ___ieee80211_stop_tx_ba_session(),
sets HT_AGG_STATE_STOPPING
From here on, the order doesn't matter exactly, but:
1. driver calls ieee80211_start_tx_ba_cb_irqsafe(),
setting HT_AGG_STATE_START_CB
2. driver calls ieee80211_stop_tx_ba_cb_irqsafe(),
setting HT_AGG_STATE_STOP_CB
3. the worker will run ieee80211_start_tx_ba_cb() for
HT_AGG_STATE_START_CB
4. the worker will run ieee80211_stop_tx_ba_cb() for
HT_AGG_STATE_STOP_CB
(the order could also be 1./3./2./4.)
This will cause ieee80211_start_tx_ba_cb() to send out the AddBA
request frame to the AP and arm the timer, but we're already in
the middle of stopping and so the ieee80211_stop_tx_ba_cb() will
no longer assume it needs to stop anything.
Prevent this by checking for WANT_STOP/STOPPING in the start CB,
and warn if we're sending a frame on a stopping session.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230618214436.e5b52777462a.I0b2ed6658e81804279f5d7c9c1918cb1f6626bf2@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/agg-tx.c')
| -rw-r--r-- | net/mac80211/agg-tx.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index 118ad2e24dbb..b6b772685881 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -457,6 +457,10 @@ static void ieee80211_send_addba_with_timeout(struct sta_info *sta, u8 tid = tid_tx->tid; u16 buf_size; + if (WARN_ON_ONCE(test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state) || + test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state))) + return; + lockdep_assert_held(&sta->ampdu_mlme.mtx); /* activate the timer for the recipient's addBA response */ @@ -802,6 +806,10 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid, if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))) return; + if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state) || + test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state)) + return; + if (!test_bit(HT_AGG_STATE_SENT_ADDBA, &tid_tx->state)) { ieee80211_send_addba_with_timeout(sta, tid_tx); /* RESPONSE_RECEIVED state whould trigger the flow again */ |