Re: [PATCH v2] pci: Limit VPD length for megaraid_sas adapter

[Myron Stowe]

On Wed, Nov 11, 2015 at 8:54 AM, Babu Moger <babu.moger@xxxxxxxxxx> wrote:
> Changes since v1 -> v2
> Removed the changes in pci_id.h. Kept all the vendor
> ids in quirks.c
>
> 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 id bffadffd43d438c3143b8d172a463de89345b836)
>
> 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 0.
>
> Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx>
> ---
>  drivers/pci/quirks.c |   38 ++++++++++++++++++++++++++++++++++++++
>  1 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index b03373f..f739e47 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2123,6 +2123,44 @@ 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.
> + * Also I dont believe vendors have implemented this VPD headers properly.
> + * Atleast I dont see it in following megaraid sas controller.
> + * That is why adding the quirk here.
> + */
> +static void quirk_megaraid_sas_limit_vpd(struct pci_dev *dev)
> +{
> +       if (dev->vpd)
> +               dev->vpd->len = 0;
> +}
> +
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0060,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x007c,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0413,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0078,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0079,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0073,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0071,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005b,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x002f,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005d,
> +               quirk_megaraid_sas_limit_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005f,
> +               quirk_megaraid_sas_limit_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
> --
> 1.7.1
>

Just to confirm, I've encountered similar results on a MegaRAID SAS 2208 -

  $ lspci -vvv -s 02:00.0
  02:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 2208
  [Thunderbolt] (rev 05)
        Capabilities: [d0] Vital Product Data
                Unknown small resource type 00, will not decode more.

  $ cat /sys/devices/pci0000:00/0000:00:02.2/0000:02:00.0/vpd |
     od -A x -t x1z -v
  000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  >................<
  *
  007ff0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  >................<
  008000

and got the following on the NIC related ports of a Brocade device -

 $ lspci -vvv -s 03:00.0
  03:00.0 Fibre Channel: Brocade Communications Systems, Inc.
  1010/1020/1007/1741 10Gbps CNA (rev 01)
        Capabilities: [a0] Vital Product Data
                No end tag found

  $ cat /sys/devices/pci0000:00/0000:00:02.0/0000:03:00.0/vpd |
     od -A x -t x1z -v
  000000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  >................<
  *
  007ff0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff  >................<
  008000


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