[PATCH v1] arm64:pci: fix the IOV device enabled crash issue in designware
Po Liu
po.liu at nxp.com
Wed Aug 24 21:53:19 PDT 2016
Hi Bjorn,
Best regards,
Liu Po
> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas at kernel.org]
> Sent: Thursday, August 25, 2016 4:51 AM
> To: Po Liu
> Cc: linux-pci at vger.kernel.org; Roy Zang; Arnd Bergmann; Stuart Yoder;
> Yang-Leo Li; linux-arm-kernel at lists.infradead.org; Bjorn Helgaas;
> Mingkai Hu; Ley Foon Tan; Michal Simek; Sören Brinkmann; Jingoo Han;
> Pratyush Anand
> Subject: Re: [PATCH v1] arm64:pci: fix the IOV device enabled crash
> issue in designware
>
> [+cc Jingoo, Pratyush, Michal, Sören, Ley]
>
> On Tue, Aug 23, 2016 at 02:01:12PM +0800, Po Liu wrote:
> > When echo a number to /sys/bus/pci/devices/xxx/sriov_numvfs to enable
> > the VF devices. A crash log occurred. This found to be access the IOV
> > devices config space failure issue.
>
> What was the actual crash? The mere fact that we made a config read
> fail should not cause a crash. We might erroneously prevent access to
> VF devices, but it shouldn't crash. So maybe there's another bug
> elsewhere that we should fix first.
I built with CONFIG_PCI_IOV=y and notice a crash when I use it:
centqds-60 cd /sys/class/net/
centqds-61 ls
enP1p1s0@ enP2p1s0f0@ enP2p1s0f1@ lo@ sit0@
centqds-62 cd enP2p1s0f1/device
centqds-63 ls
broken_parity_status driver_override msi_irqs/ sriov_numvfs
class enable net/ sriov_totalvfs
config iommu_group@ power/ subsystem@
consistent_dma_mask_bits irq remove subsystem_device
device local_cpulist rescan subsystem_vendor
devspec local_cpus reset uevent
dma_mask_bits modalias resource vendor
driver@ msi_bus rom
centqds-64 zcat /proc/config.gz | grep _IOV
CONFIG_PCI_IOV=y
centqds-65 sudo su
[root at centqds 0002:01:00.1]# echo 2 > sriov_numvfs
[ 317.604543] ixgbe 0002:01:00.1 enP2p1s0f1: SR-IOV enabled with 2 VFs
[ 317.714431] (null): of_irq_parse_pci() failed with rc=134
[ 317.719906] -----------[ cut here ]-----------
[ 317.724525] WARNING: CPU: 6 PID: 3179 at drivers/pci/probe.c:1555 pci_device_add+0x144/0x148()
[ 317.733123] Modules linked in:
[ 317.736175] CPU: 6 PID: 3179 Comm: bash Not tainted 4.1.8-00024-g0a32d65-dirty #32
[ 317.743731] Hardware name: Freescale Layerscape 2088a QDS Board (DT)
[ 317.750077] Call trace:
[ 317.752516] [<fffffe0000096cf8>] dump_backtrace+0x0/0x12c
Message from[ 317.757916] [<fffffe0000096e34>] show_stack+0x10/0x1c
syslogd at centqds[ 317.764341] [<fffffe00008937fc>] dump_stack+0x84/0xd4
at Jul 26 15:51[ 317.770770] [<fffffe00000be590>] warn_slowpath_common+0x94/0xcc
:10 ...
kerne[ 317.778067] [<fffffe00000be68c>] warn_slowpath_null+0x14/0x20
l:Call trace:
[ 317.785192] [<fffffe00003c5fa4>] pci_device_add+0x140/0x148
[ 317.792133] [<fffffe00003de784>] pci_enable_sriov+0x470/0x7a0
[ 317.797873] [<fffffe00005fa9dc>] ixgbe_pci_sriov_configure+0x8c/0x148
[ 317.804302] [<fffffe00003cf354>] sriov_numvfs_store+0x78/0x11c
[ 317.810129] [<fffffe0000443d80>] dev_attr_store+0x14/0x28
[ 317.815521] [<fffffe0000200164>] sysfs_kf_write+0x40/0x4c
[ 317.820908] [<fffffe00001ff5ec>] kernfs_fop_write+0xb8/0x180
[ 317.826561] [<fffffe000019a568>] __vfs_write+0x28/0x10c
[ 317.831775] [<fffffe000019ad00>] vfs_write+0x90/0x1a0
[ 317.836819] [<fffffe000019b584>] SyS_write+0x40/0xa0
[ 317.841772] --[ end trace 83725a9784fd702a ]--
[ 317.846393] BUG: failure at fs/sysfs/file.c:481/sysfs_create_bin_file()!
[ 317.853081] Kernel panic - not syncing: BUG!
[ 317.857339] CPU: 6 PID: 3179 Comm: bash Tainted: G W 4.1.8-00024-g0a32d65-dirty #32
[ 317.866110] Hardware name: Freescale Layerscape 2088a QDS Board (DT)
[ 317.872451] Call trace:
[ 317.874887] [<fffffe0000096cf8>] dump_backtrace+0x0/0x12c
[ 317.880274] [<fffffe0000096e34>] show_stack+0x10/0x1c
[ 317.885315] [<fffffe00008937fc>] dump_stack+0x84/0xd4
[ 317.890354] [<fffffe00008909e8>] panic+0xe4/0x21c
[ 317.895047] [<fffffe0000200988>] sysfs_create_bin_file+0x60/0x64
[ 317.901041] [<fffffe00003cf52c>] pci_create_sysfs_dev_files+0x48/0x2a8
[ 317.907556] [<fffffe00003c4238>] pci_bus_add_device+0x20/0x6c
The code process is that: "echo 2 > sriov_numvf" makes driver load .sriov_configure. At last to load pci_enable_sriov().
The first time vf device operate the config space in the pci_setup_device() (this function was load in the virtfn_add()) is pci_read_config_byte(dev, PCI_HEADER_TYPE, &hdr_type) return failure. So the virtfn didn't initialized proper.
This found to be "bus->primary == pp->root_bus_nr && dev > 0" then return failure in host controller. The dev came from devfn must not zero(is about 0x10).
then read config space failure. This makes the dev->bus is NULL. Lead to upper crash.
>
> > The read/write config space from host would judge the pcie device
> > plugin or not by:
> >
> > if (bus->primary == pp->root_bus_nr && dev > 0)
> > return 0;
>
> I'm guessing other drivers have the same issue, e.g.,
> altera_pcie_valid_config(), xilinx_pcie_valid_device().
>
> Can you look through them and fix them all at once?
Ok, if the problem is same.
>
> > Although all pcie devices for dev(coming from the device and function
> > number) is zero. But the dev is not zero for VF. So remove the
> > condition.
> >
> > Signed-off-by: Po Liu <po.liu at nxp.com>
> > ---
> > drivers/pci/host/pcie-designware.c | 7 -------
> > 1 file changed, 7 deletions(-)
> >
> > diff --git a/drivers/pci/host/pcie-designware.c
> > b/drivers/pci/host/pcie-designware.c
> > index 12afce1..dd20eb2 100644
> > --- a/drivers/pci/host/pcie-designware.c
> > +++ b/drivers/pci/host/pcie-designware.c
> > @@ -670,13 +670,6 @@ static int dw_pcie_valid_config(struct pcie_port
> *pp,
> > if (bus->number == pp->root_bus_nr && dev > 0)
> > return 0;
> >
> > - /*
> > - * do not read more than one device on the bus directly attached
> > - * to RC's (Virtual Bridge's) DS side.
> > - */
> > - if (bus->primary == pp->root_bus_nr && dev > 0)
> > - return 0;
> > -
> > return 1;
> > }
> >
> > --
> > 2.1.0.27.g96db324
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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