Re: [PATCH v10 02/26] sfc: add basic cxl initialization

[Simon Horman <horms@kernel.org>]

On Wed, Feb 05, 2025 at 03:19:26PM +0000, alucerop@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> Create a cxl_memdev_state with CXL_DEVTYPE_DEVMEM, aka CXL Type2 memory
> device.
> 
> Make sfc CXL initialization dependent on kernel CXL configuration.
> 
> Signed-off-by: Alejandro Lucero <alucerop@amd.com>

...

> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
> new file mode 100644
> index 000000000000..69feffd4aec3
> --- /dev/null
> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
> @@ -0,0 +1,60 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/****************************************************************************
> + *
> + * Driver for AMD network controllers and boards
> + * Copyright (C) 2024, Advanced Micro Devices, Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published
> + * by the Free Software Foundation, incorporated herein by reference.
> + */
> +
> +#include <cxl/pci.h>
> +#include <cxl/cxl.h>
> +#include <linux/pci.h>
> +
> +#include "net_driver.h"
> +#include "efx_cxl.h"
> +
> +#define EFX_CTPIO_BUFFER_SIZE	SZ_256M
> +
> +int efx_cxl_init(struct efx_probe_data *probe_data)
> +{
> +	struct efx_nic *efx = &probe_data->efx;
> +	struct pci_dev *pci_dev = efx->pci_dev;
> +	struct efx_cxl *cxl;
> +	u16 dvsec;
> +
> +	probe_data->cxl_pio_initialised = false;
> +
> +	dvsec = pci_find_dvsec_capability(pci_dev, PCI_VENDOR_ID_CXL,
> +					  CXL_DVSEC_PCIE_DEVICE);
> +	if (!dvsec)
> +		return 0;
> +
> +	pci_dbg(pci_dev, "CXL_DVSEC_PCIE_DEVICE capability found\n");
> +
> +	cxl = kzalloc(sizeof(*cxl), GFP_KERNEL);
> +	if (!cxl)
> +		return -ENOMEM;
> +
> +	cxl->cxlmds = cxl_memdev_state_create(&pci_dev->dev, pci_dev->dev.id,
> +					      dvsec, CXL_DEVTYPE_DEVMEM);
> +
> +	if (IS_ERR(cxl->cxlmds)) {
> +		kfree(cxl);

Hi Alejandro,

cxl is freed on the line above but dereferenced on the line below.

> +		return PTR_ERR(cxl->cxlmds);
> +	}
> +
> +	probe_data->cxl = cxl;
> +
> +	return 0;
> +}

...