netdev - [PATCH] enic: Fix a sleep-in-atomic bug

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Date:   Wed, 31 May 2017 10:34:49 +0800
From:   Jia-Ju Bai <baijiaju1990@....com>
To:     benve@...co.com, _govind@....com, neepatel@...co.com
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@....com>
Subject: [PATCH] enic: Fix a sleep-in-atomic bug

The driver may sleep under a spin lock in some function call paths.
The 1st function call path is:
enic_reset (acquire the lock by spin_lock)
  enic_stop
    enic_synchronize_irqs
      synchronize_irq --> may sleep
The 2nd function call path is:
enic_reset (acquire the lock by spin_lock)
  enic_dev_soft_reset
    enic_dev_wait
      schedule_timeout_uninterruptible --> may sleep
The 3rd function call path is:
enic_reset (acquire the lock by spin_lock)
  enic_open
    enic_request_intr
      enic_set_rx_cpu_rmap
        enic_free_rx_cpu_rmap
          free_irq_cpu_rmap --> may sleep

To fix it, the "spin_lock" and "spin_unlock" are removed in enic_reset.

Signed-off-by: Jia-Ju Bai <baijiaju1990@....com>
---
 drivers/net/ethernet/cisco/enic/enic_main.c |    2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index 4b87bee..2a9bef8 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -2310,7 +2310,6 @@ static void enic_reset(struct work_struct *work)
 
 	rtnl_lock();
 
-	spin_lock(&enic->enic_api_lock);
 	enic_stop(enic->netdev);
 	enic_dev_soft_reset(enic);
 	enic_reset_addr_lists(enic);
@@ -2318,7 +2317,6 @@ static void enic_reset(struct work_struct *work)
 	enic_set_rss_nic_cfg(enic);
 	enic_dev_set_ig_vlan_rewrite_mode(enic);
 	enic_open(enic->netdev);
-	spin_unlock(&enic->enic_api_lock);
 	call_netdevice_notifiers(NETDEV_REBOOT, enic->netdev);
 
 	rtnl_unlock();
-- 
1.7.9.5