package/kernel/mac80211/patches/311-ath10k-fix-deadlock-while-processing-rx_in_ord_ind.patch

   1 From: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
   2 Date: Thu, 9 Jun 2016 11:33:55 +0530
   3 Subject: [PATCH] ath10k: fix deadlock while processing rx_in_ord_ind
   4
   5 commit 5c86d97bcc1d ("ath10k: combine txrx and replenish task")
   6 introduced deadlock while processing rx in order indication message
   7 for qca6174 based devices. While merging replenish and txrx tasklets,
   8 replenish task should be called out of htt rx ring locking since it
   9 is also try to acquire the same lock.
  10
  11 Unfortunately this issue is not exposed by other solutions (qca988x,
  12 qca99x0 & qca4019), as rx_in_ord_ind message is specific to qca6174
  13 based devices. This patch fixes
  14
  15 =============================================
  16 [ INFO: possible recursive locking detected ]
  17 4.7.0-rc2-wt-ath+ #1353 Tainted: G            E
  18 ---------------------------------------------
  19 swapper/3/0 is trying to acquire lock:
  20  (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d7ef19>]
  21 ath10k_htt_rx_msdu_buff_replenish+0x29/0x90 [ath10k_core]
  22
  23 but task is already holding lock:
  24  (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d82cab>]
  25 ath10k_htt_txrx_compl_task+0x21b/0x250 [ath10k_core]
  26
  27 other info that might help us debug this:
  28  Possible unsafe locking scenario:
  29
  30        CPU0
  31        ----
  32   lock(&(&htt->rx_ring.lock)->rlock);
  33   lock(&(&htt->rx_ring.lock)->rlock);
  34
  35  *** DEADLOCK ***
  36
  37  May be due to missing lock nesting notation
  38
  39 1 lock held by swapper/3/0:
  40  #0:  (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d82cab>]
  41 ath10k_htt_txrx_compl_task+0x21b/0x250 [ath10k_core]
  42
  43 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=119151
  44 Fixes: 5c86d97bcc1d ("ath10k: combine txrx and replenish task")
  45 Reported-by: Mike Lothian <mike@fireburn.co.uk>
  46 Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
  47 Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
  48 ---
  49
  50 --- a/drivers/net/wireless/ath/ath10k/htt_rx.c
  51 +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
  52 @@ -1904,7 +1904,6 @@ static void ath10k_htt_rx_in_ord_ind(str
  53                         return;
  54                 }
  55         }
  56 -       ath10k_htt_rx_msdu_buff_replenish(htt);
  57  }
  58
  59  static void ath10k_htt_rx_tx_fetch_resp_id_confirm(struct ath10k *ar,