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ath10k: fix deadlock while processing rx_in_ord_ind
authorRajkumar Manoharan <rmanohar@qti.qualcomm.com>
Thu, 9 Jun 2016 06:03:55 +0000 (11:33 +0530)
committerKalle Valo <kvalo@qca.qualcomm.com>
Tue, 14 Jun 2016 12:06:17 +0000 (15:06 +0300)
commite50525bef593c3dd0564df676c567d77f7c20322
tree7bb3fd61a7df7ceb388cb975f82de69886415b28
parent8d0a0710ea0d22881fdb40eb79d346a98cc64ae6
ath10k: fix deadlock while processing rx_in_ord_ind

commit 5c86d97bcc1d ("ath10k: combine txrx and replenish task")
introduced deadlock while processing rx in order indication message
for qca6174 based devices. While merging replenish and txrx tasklets,
replenish task should be called out of htt rx ring locking since it
is also try to acquire the same lock.

Unfortunately this issue is not exposed by other solutions (qca988x,
qca99x0 & qca4019), as rx_in_ord_ind message is specific to qca6174
based devices. This patch fixes

=============================================
[ INFO: possible recursive locking detected ]
4.7.0-rc2-wt-ath+ #1353 Tainted: G            E
---------------------------------------------
swapper/3/0 is trying to acquire lock:
 (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d7ef19>]
ath10k_htt_rx_msdu_buff_replenish+0x29/0x90 [ath10k_core]

but task is already holding lock:
 (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d82cab>]
ath10k_htt_txrx_compl_task+0x21b/0x250 [ath10k_core]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&htt->rx_ring.lock)->rlock);
  lock(&(&htt->rx_ring.lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

1 lock held by swapper/3/0:
 #0:  (&(&htt->rx_ring.lock)->rlock){+.-...}, at: [<f8d82cab>]
ath10k_htt_txrx_compl_task+0x21b/0x250 [ath10k_core]

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=119151
Fixes: 5c86d97bcc1d ("ath10k: combine txrx and replenish task")
Reported-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Rajkumar Manoharan <rmanohar@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
drivers/net/wireless/ath/ath10k/htt_rx.c