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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Taehee Yoo <ap420073@gmail.com>,
        Andrew Bowers <andrewx.bowers@intel.com>,
        Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
        "David S . Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.2 15/76] ixgbe: fix possible deadlock in ixgbe_service_task()
Date:   Thu, 29 Aug 2019 14:12:10 -0400
Message-Id: <20190829181311.7562-15-sashal@kernel.org>
In-Reply-To: <20190829181311.7562-1-sashal@kernel.org>
References: <20190829181311.7562-1-sashal@kernel.org>
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From: Taehee Yoo <ap420073@gmail.com>

[ Upstream commit 8b6381600d59871fbe44d36522272f961ab42410 ]

ixgbe_service_task() calls unregister_netdev() under rtnl_lock().
But unregister_netdev() internally calls rtnl_lock().
So deadlock would occur.

Fixes: 59dd45d550c5 ("ixgbe: firmware recovery mode")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 57fd9ee6de665..f7c049559c1a5 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7893,11 +7893,8 @@ static void ixgbe_service_task(struct work_struct *work)
 		return;
 	}
 	if (ixgbe_check_fw_error(adapter)) {
-		if (!test_bit(__IXGBE_DOWN, &adapter->state)) {
-			rtnl_lock();
+		if (!test_bit(__IXGBE_DOWN, &adapter->state))
 			unregister_netdev(adapter->netdev);
-			rtnl_unlock();
-		}
 		ixgbe_service_event_complete(adapter);
 		return;
 	}
-- 
2.20.1