linux-kernel - Re: [PATCHv2 4/4] pci: Blacklist vpd access for buggy devices

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Date:	Tue, 9 Feb 2016 15:07:59 -0600
From:	Bjorn Helgaas <helgaas@...nel.org>
To:	Hannes Reinecke <hare@...e.de>
Cc:	Alexander Duyck <alexander.duyck@...il.com>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Babu Moger <babu.moger@...cle.com>
Subject: Re: [PATCHv2 4/4] pci: Blacklist vpd access for buggy devices

There seem to be several revs of this patch, and it's hard for me to
keep track of what's current.  If you want to update any patch in the
series, please repost the entire series with a new version number.

On Wed, Jan 13, 2016 at 12:25:35PM +0100, Hannes Reinecke wrote:
> From: Babu Moger <babu.moger@...cle.com>
> 
> Reading or Writing of PCI VPD data causes system panic.
> We saw this problem by running "lspci -vvv" in the beginning.
> However this can be easily reproduced by running
>  cat /sys/bus/devices/XX../vpd
> 
> As even a simple read on any VPD data triggers a system
> lockup on certain cards this patch implements a PCI quirk
> to disabling VPD acces altogether by setting the vpd length

s/acces/access/
s/vpd/VPD/

> to '0'.
> 
> Signed-off-by: Babu Moger <babu.moger@...cle.com>
> Signed-off-by: Hannes Reinecke <hare@...e.de>
> ---
>  drivers/pci/access.c |  5 ++++-
>  drivers/pci/quirks.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 914e023..82f41a8 100644
> --- a/drivers/pci/access.c
> +++ b/drivers/pci/access.c
> @@ -396,7 +396,7 @@ static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
>  	if (pos < 0)
>  		return -EINVAL;
>  
> -	if (!vpd->valid) {
> +	if (!vpd->valid && vpd->base.len > 0) {
>  		vpd->valid = true;
>  		vpd->base.len = pci_vpd_pci22_size(dev);
>  	}
> @@ -459,6 +459,9 @@ static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count
>  	loff_t end = pos + count;
>  	int ret = 0;
>  
> +	if (vpd->base.len == 0)
> +		return -EIO;
> +
>  	if (!vpd->valid)
>  		return -EAGAIN;
>  
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 7e32730..af0f8a1 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2123,6 +2123,47 @@ static void quirk_via_cx700_pci_parking_caching(struct pci_dev *dev)
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, 0x324e, quirk_via_cx700_pci_parking_caching);
>  
>  /*
> + * A read/write to sysfs entry ('/sys/bus/pci/devices/<id>/vpd')
> + * will dump 32k of data. The default length is set as 32768.
> + * Reading a full 32k will cause an access beyond the VPD end tag.
> + * The system behaviour at that point is mostly unpredictable.
> + * Apparently, some vendors have not implemented this VPD headers properly.
> + * Adding a generic function disable vpd data for these buggy adapters
> + * Add the DECLARE_PCI_FIXUP_FINAL line below with the specific with
> + * vendor and device of interest to use this quirk.
> + */
> +static void quirk_blacklist_vpd(struct pci_dev *dev)
> +{
> +	if (dev->vpd) {
> +		dev->vpd->len = 0;
> +		dev_warn(&dev->dev, "PCI vpd access has been disabled due to firmware bug\n");

"PCI" is superfluous and "VPD" should be capitalized.

> +	}
> +}
> +
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0060,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x007c,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0413,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0078,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0079,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0073,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0071,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005b,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x002f,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005d,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005f,
> +		quirk_blacklist_vpd);
> +
> +/*
>   * For Broadcom 5706, 5708, 5709 rev. A nics, any read beyond the
>   * VPD end tag will hang the device.  This problem was initially
>   * observed when a vpd entry was created in sysfs
> -- 
> 1.8.5.6
> 
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