[PATCH 4.4 026/124] iwlwifi: pcie: fix race in Rx buffer allocator

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Shaul Triebitz <shaul.triebitz@xxxxxxxxx>

[ Upstream commit 0f22e40053bd5378ad1e3250e65c574fd61c0cd6 ]

Make sure the rx_allocator worker is canceled before running the
rx_init routine.  rx_init frees and re-allocates all rxb's pages.  The
rx_allocator worker also allocates pages for the used rxb's.  Running
rx_init and rx_allocator simultaniously causes a kernel panic.  Fix
that by canceling the work in rx_init.

Signed-off-by: Shaul Triebitz <shaul.triebitz@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/wireless/iwlwifi/pcie/rx.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -713,6 +713,8 @@ int iwl_pcie_rx_init(struct iwl_trans *t
 						WQ_HIGHPRI | WQ_UNBOUND, 1);
 	INIT_WORK(&rba->rx_alloc, iwl_pcie_rx_allocator_work);
 
+	cancel_work_sync(&rba->rx_alloc);
+
 	spin_lock(&rba->lock);
 	atomic_set(&rba->req_pending, 0);
 	atomic_set(&rba->req_ready, 0);