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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Shaul Triebitz <shaul.triebitz@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.4 026/124] iwlwifi: pcie: fix race in Rx buffer allocator
Date:   Sat,  4 Aug 2018 11:00:15 +0200
Message-Id: <20180804082703.421702408@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

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

From: Shaul Triebitz <shaul.triebitz@intel.com>

[ 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@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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);