Re: [PATCH] nvme-pci: Fix NULL ptr deref in EEH code

[Christoph Hellwig]

On Tue, Mar 20, 2018 at 11:22:42AM +1100, Michael Neuling wrote:
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index b6f43b738f..404b346e3c 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2626,6 +2626,9 @@ static pci_ers_result_t nvme_error_detected(struct pci_dev *pdev,
>  {
>  	struct nvme_dev *dev = pci_get_drvdata(pdev);
>  
> +	if (!dev)
> +		return PCI_ERS_RESULT_NEED_RESET;

This implies the method has been called before ->probe has been finished
or after ->remove has been called.  That would be fundamentally racy
and needs to be fixed in the PCI layer, not papered over in drivers.