Re: [PATCH -3.2.y] igb: Fix locking to silence ASSERT_RTNL() warning during suspend/resume

[Ben Hutchings]

On Mon, 2012-03-26 at 17:37 +0530, Srivatsa S. Bhat wrote:
> From: Zheng Yan <zheng.z....@intel.com>
> 
> [ Upstream commit 749ab2cd127046df79084b6b9165b23491b1db5f ]
> 
> During suspend/resume (and possibly in other scenarios as well), the
> ASSERT_RTNL() warning is triggered in netif_set_real_num_tx/rx_queues()
> functions, something like:
[...]
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c 
> b/drivers/net/ethernet/intel/igb/igb_main.c
> index 222954d..8775087 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -6697,7 +6697,18 @@ static int igb_resume(struct pci_dev *pdev)
>       pci_enable_wake(pdev, PCI_D3hot, 0);
>       pci_enable_wake(pdev, PCI_D3cold, 0);
>  
> -     if (igb_init_interrupt_scheme(adapter)) {
> +     if (!rtnl_is_locked()) {

This doesn't tell whether this process holds the lock.  So it suppresses
the warning but doesn't fix the real bug.

Ben.

> +             /*
> +              * shut up ASSERT_RTNL() warning in
> +              * netif_set_real_num_tx/rx_queues.
> +              */
> +             rtnl_lock();
> +             err = igb_init_interrupt_scheme(adapter);
> +             rtnl_unlock();
> +     } else {
> +             err = igb_init_interrupt_scheme(adapter);
> +     }
> +     if (err) {
>               dev_err(&pdev->dev, "Unable to allocate memory for queues\n");
>               return -ENOMEM;
>       }


-- 
Ben Hutchings
Horngren's Observation:
                   Among economists, the real world is often a special case.

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