Re: [PATCH net] e1000e: roll back registered MSI-X IRQs on failure

[Paul Menzel <pmenzel@molgen.mpg.de>]

Dear Runyu,


Thank you for your patch.

Am 14.09.26 um 16:20 schrieb Runyu Xiao:
> e1000_request_msix() requests the RX, TX, and other-cause interrupt
> handlers sequentially. If a later request_irq() fails, the function
> returns without releasing handlers that were registered earlier. The
> caller then disables MSI-X and falls back to MSI or legacy interrupts,
> leaving those handlers registered against disabled MSI-X vectors.
> 
> Free all handlers registered before the failing request in reverse order
> before returning the error. The failed vector is not freed, and the
> existing fallback path can then disable MSI-X without retaining stale
> handlers.
> 
> A QEMU e1000e test with deterministic failure injection at the third
> request_irq() reproduced a residual IRQ entry and warning on the
> unfixed kernel. The fixed kernel reached the same fallback without the
> residual entry. The injection is deliberate and does not claim that a
> third request_irq() failure occurs spontaneously during normal operation.

Could you please amend the commit message, and give more information how 
to reproduce this exactly, and get the warning?

> Fixes: 4662e82b2cb4 ("e1000e: add support for new 82574L part")
> Cc: stable@vger.kernel.org
> Assisted-by: LLM Codex

Please add the version.

> Signed-off-by: Runyu Xiao <runyu.xiao@seu.edu.cn>
> ---
>   drivers/net/ethernet/intel/e1000e/netdev.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 844f31ab37ad4..f55aec340342b 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -2139,7 +2139,7 @@ static int e1000_request_msix(struct e1000_adapter *adapter)
>   			  e1000_intr_msix_tx, 0, adapter->tx_ring->name,
>   			  netdev);
>   	if (err)
> -		return err;
> +		goto err_irq;
>   	adapter->tx_ring->itr_register = adapter->hw.hw_addr +
>   	    E1000_EITR_82574(vector);
>   	adapter->tx_ring->itr_val = adapter->itr;
> @@ -2148,11 +2148,16 @@ static int e1000_request_msix(struct e1000_adapter *adapter)
>   	err = request_irq(adapter->msix_entries[vector].vector,
>   			  e1000_msix_other, 0, netdev->name, netdev);
>   	if (err)
> -		return err;
> +		goto err_irq;
>   
>   	e1000_configure_msix(adapter);
>   
>   	return 0;
> +
> +err_irq:
> +	while (vector)
> +		free_irq(adapter->msix_entries[--vector].vector, netdev);
> +	return err;
>   }
>   
>   /**

The diff looks good.


Kind regards,

Paul