Re: [PATCH RFC] pci: Blacklist vpd access for buggy devices

From: Babu Moger <babu.moger@oracle.com>
To: bhelgaas@google.com
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	alexander.duyck@gmail.com, hare@suse.de, mkubecek@suse.com,
	shane.seymour@hpe.com, myron.stowe@gmail.com,
	VenkatKumar.Duvvuru@avago.com,
	Jordan Hargrave <Jordan_Hargrave@dell.com>
Subject: Re: [PATCH RFC] pci: Blacklist vpd access for buggy devices
Date: Mon, 11 Jan 2016 16:49:40 -0600	[thread overview]
Message-ID: <56943184.3060303@oracle.com> (raw)
In-Reply-To: <1452546789-62938-1-git-send-email-babu.moger@oracle.com>

Sorry. Missed Jordan.

On 1/11/2016 3:13 PM, Babu Moger wrote:
> 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
> 
> VPD length has been set as 32768 by default. Accessing vpd
> will trigger read/write of 32k. This causes problem as we
> could read data beyond the VPD end tag. Behaviour is un-
> predictable when this happens. I see some other adapter doing
> similar quirks(commit bffadffd43d4 ("PCI: fix VPD limit quirk
> for Broadcom 5708S"))
> 
> I see there is an attempt to fix this right way.
> https://patchwork.ozlabs.org/patch/534843/ or
> https://lkml.org/lkml/2015/10/23/97
> 
> Tried to fix it this way, but problem is I dont see the proper
> start/end TAGs(at least for this adapter) at all. The data is
> mostly junk or zeros. This patch fixes the issue by setting the
> vpd length to 0x80.
> 
> Also look at the threds 
> 
> https://lkml.org/lkml/2015/11/10/557
> https://lkml.org/lkml/2015/12/29/315
> 
> Signed-off-by: Babu Moger <babu.moger@oracle.com>
> ---
> 
> NOTE:
> Jordan, Are you sure all the devices in PCI_VENDOR_ID_ATHEROS and
> PCI_VENDOR_ID_ATTANSIC have this problem. You have used PCI_ANY_ID.
> I felt it is too broad. Can you please check.
> 
> 
>  drivers/pci/quirks.c |   41 +++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 41 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b03373f..8abcee5 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");
> +	}
> +}
> +
> +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
> 