Messages in this thread Patch in this message | | | From | Babu Moger <> | Subject | [PATCH v4] pci: Limit VPD length for megaraid_sas adapter | Date | Thu, 3 Dec 2015 12:25:19 -0800 |
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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.
Signed-off-by: Babu Moger <babu.moger@oracle.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Tested-by: Dmitry Klochkov <dmitry.klochkov@oracle.com>
Orabug: 22104511
Changes since v3 -> v4 We found some options of the lspci does not work very well if it cannot find the valid vpd tag(Example command "lspci -s 10:00.0 -vv"). It displays the error message and exits right away. Setting the length back to 0 fixes the problem.
Changes since v2 -> v3 Changed the vpd length from 0 to 0x80 which leaves the option open for someone to read first few bytes.
Changes since v1 -> v2 Removed the changes in pci_id.h. Kept all the vendor ids in quirks.c --- 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
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