From 0faf745872f6d00afb318185e8fb181587974b5a Mon Sep 17 00:00:00 2001 From: Vasanthakumar Thiagarajan Date: Wed, 30 May 2012 12:27:11 +0530 Subject: [PATCH] ath6kl: Fix race in aggregation reorder logic There are many places where tid data are accessed without the lock (rxtid->lock), this can lead to a race condition when the timeout handler for aggregatin reorder and the receive function are getting executed at the same time. Fix this race, but still there are races which can not be fixed without rewriting the whole aggregation reorder logic, for now fix the obvious ones. Signed-off-by: Vasanthakumar Thiagarajan Signed-off-by: Kalle Valo --- drivers/net/wireless/ath/ath6kl/core.h | 12 +++++++++--- drivers/net/wireless/ath/ath6kl/txrx.c | 12 +++++++++--- 2 files changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/net/wireless/ath/ath6kl/core.h b/drivers/net/wireless/ath/ath6kl/core.h index 17a44fad859..12441f7d903 100644 --- a/drivers/net/wireless/ath/ath6kl/core.h +++ b/drivers/net/wireless/ath/ath6kl/core.h @@ -273,9 +273,15 @@ struct rxtid { struct sk_buff_head q; /* - * FIXME: No clue what this should protect. Apparently it should - * protect some of the fields above but they are also accessed - * without taking the lock. + * lock mainly protects seq_next and hold_q. Movement of seq_next + * needs to be protected between aggr_timeout() and + * aggr_process_recv_frm(). hold_q will be holding the pending + * reorder frames and it's access should also be protected. + * Some of the other fields like hold_q_sz, win_sz and aggr are + * initialized/reset when receiving addba/delba req, also while + * deleting aggr state all the pending buffers are flushed before + * resetting these fields, so there should not be any race in accessing + * these fields. */ spinlock_t lock; }; diff --git a/drivers/net/wireless/ath/ath6kl/txrx.c b/drivers/net/wireless/ath/ath6kl/txrx.c index 67206aedea6..974c51053a7 100644 --- a/drivers/net/wireless/ath/ath6kl/txrx.c +++ b/drivers/net/wireless/ath/ath6kl/txrx.c @@ -1036,6 +1036,7 @@ static void aggr_deque_frms(struct aggr_info_conn *agg_conn, u8 tid, rxtid = &agg_conn->rx_tid[tid]; stats = &agg_conn->stat[tid]; + spin_lock_bh(&rxtid->lock); idx = AGGR_WIN_IDX(rxtid->seq_next, rxtid->hold_q_sz); /* @@ -1054,8 +1055,6 @@ static void aggr_deque_frms(struct aggr_info_conn *agg_conn, u8 tid, seq_end = seq_no ? seq_no : rxtid->seq_next; idx_end = AGGR_WIN_IDX(seq_end, rxtid->hold_q_sz); - spin_lock_bh(&rxtid->lock); - do { node = &rxtid->hold_q[idx]; if ((order == 1) && (!node->skb)) @@ -1127,11 +1126,13 @@ static bool aggr_process_recv_frm(struct aggr_info_conn *agg_conn, u8 tid, ((end > extended_end) && (cur > extended_end) && (cur < end))) { aggr_deque_frms(agg_conn, tid, 0, 0); + spin_lock_bh(&rxtid->lock); if (cur >= rxtid->hold_q_sz - 1) rxtid->seq_next = cur - (rxtid->hold_q_sz - 1); else rxtid->seq_next = ATH6KL_MAX_SEQ_NO - (rxtid->hold_q_sz - 2 - cur); + spin_unlock_bh(&rxtid->lock); } else { /* * Dequeue only those frames that are outside the @@ -1186,7 +1187,8 @@ static bool aggr_process_recv_frm(struct aggr_info_conn *agg_conn, u8 tid, if (agg_conn->timer_scheduled) rxtid->progress = true; - else + else { + spin_lock_bh(&rxtid->lock); for (idx = 0 ; idx < rxtid->hold_q_sz; idx++) { if (rxtid->hold_q[idx].skb) { /* @@ -1204,6 +1206,8 @@ static bool aggr_process_recv_frm(struct aggr_info_conn *agg_conn, u8 tid, break; } } + spin_unlock_bh(&rxtid->lock); + } return is_queued; } @@ -1626,6 +1630,7 @@ static void aggr_timeout(unsigned long arg) rxtid = &aggr_conn->rx_tid[i]; if (rxtid->aggr && rxtid->hold_q) { + spin_lock_bh(&rxtid->lock); for (j = 0; j < rxtid->hold_q_sz; j++) { if (rxtid->hold_q[j].skb) { aggr_conn->timer_scheduled = true; @@ -1634,6 +1639,7 @@ static void aggr_timeout(unsigned long arg) break; } } + spin_unlock_bh(&rxtid->lock); if (j >= rxtid->hold_q_sz) rxtid->timer_mon = false; -- 2.20.1