[BNX2]: Fix rtnl deadlock in bnx2_close

This fixes an rtnl deadlock problem when flush_scheduled_work() is
called from bnx2_close(). In rare cases, linkwatch_event() may be on
the workqueue from a previous close of a different device and it will
try to get the rtnl lock which is already held by dev_close().

The fix is to set a flag if we are in the reset task which is run
from the workqueue. bnx2_close() will loop until the flag is cleared.
As suggested by Jeff Garzik, the loop is changed to call msleep(1)
instead of yield() in the original patch.

flush_scheduled_work() is also moved to bnx2_remove_one() before the
netdev is freed.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 3a9d6a8b90a20a887b32f1e3befae76a183417ea..635a5856102b9d42c830a37067e21abfc0435b87 100644 (file)
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -3975,12 +3975,17 @@ bnx2_reset_task(void *data)
 {
        struct bnx2 *bp = data;
 
+       if (!netif_running(bp->dev))
+               return;
+
+       bp->in_reset_task = 1;
        bnx2_netif_stop(bp);
 
        bnx2_init_nic(bp);
 
        atomic_set(&bp->intr_sem, 1);
        bnx2_netif_start(bp);
+       bp->in_reset_task = 0;
 }
 
 static void
@@ -4172,7 +4177,13 @@ bnx2_close(struct net_device *dev)
        struct bnx2 *bp = dev->priv;
        u32 reset_code;
 
-       flush_scheduled_work();
+       /* Calling flush_scheduled_work() may deadlock because
+        * linkwatch_event() may be on the workqueue and it will try to get
+        * the rtnl_lock which we are holding.
+        */
+       while (bp->in_reset_task)
+               msleep(1);
+
        bnx2_netif_stop(bp);
        del_timer_sync(&bp->timer);
        if (bp->wol)
@@ -5453,6 +5464,8 @@ bnx2_remove_one(struct pci_dev *pdev)
        struct net_device *dev = pci_get_drvdata(pdev);
        struct bnx2 *bp = dev->priv;
 
+       flush_scheduled_work();
+
        unregister_netdev(dev);
 
        if (bp->regview)

diff --git a/drivers/net/bnx2.h b/drivers/net/bnx2.h
index 8214a2853d0df92a71545348bb70a506fce23ee4..63b94ca0018b280998e64e5eaacf0e857be999df 100644 (file)
--- a/drivers/net/bnx2.h
+++ b/drivers/net/bnx2.h
@@ -3874,6 +3874,7 @@ struct bnx2 {
        int                     timer_interval;
        struct                  timer_list timer;
        struct work_struct      reset_task;
+       int                     in_reset_task;
 
        /* Used to synchronize phy accesses. */
        spinlock_t              phy_lock;