[PATCH v1] arm64:pci: fix the IOV device enabled crash issue in designware
Po Liu
po.liu at nxp.com
Fri Aug 26 01:17:48 PDT 2016
Hi Bjorn,
Best regards,
Liu Po
> -----Original Message-----
> From: Bjorn Helgaas [mailto:helgaas at kernel.org]
> Sent: Friday, August 26, 2016 2:10 AM
> To: Po Liu
> Cc: S?ren Brinkmann; Roy Zang; Arnd Bergmann; linux-pci at vger.kernel.org;
> Pratyush Anand; Stuart Yoder; Yang-Leo Li; Mingkai Hu; Jingoo Han; Bjorn
> Helgaas; Ley Foon Tan; Michal Simek; linux-arm-
> kernel at lists.infradead.org
> Subject: Re: [PATCH v1] arm64:pci: fix the IOV device enabled crash
> issue in designware
>
> On Thu, Aug 25, 2016 at 04:53:19AM +0000, Po Liu wrote:
> > > -----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.
>
> I think the crash (BUG: failure at
> fs/sysfs/file.c:481/sysfs_create_bin_file())
> happens in this path:
>
> sriov_numvfs_store
> ixgbe_pci_sriov_configure
> ixgbe_pci_sriov_enable
> pci_enable_sriov
> sriov_enable
> pci_iov_add_virtfn
> virtfn = pci_alloc_dev()
> pci_setup_device(virtfn)
> if (pci_read_config_byte(dev, PCI_HEADER_TYPE,
> &hdr_type))
> return -EIO
> pci_bus_add_device(virtfn)
> pci_create_sysfs_dev_files
> sysfs_create_bin_file
> BUG_ON(!kobj)
>
> If the config read of PCI_HEADER_TYPE fails, pci_setup_device() returns
> -EIO, but pci_iov_add_virtfn() doesn't check it. Can you update
> pci_iov_add_virtfn() so it checks that return value? That should fix
> the crash, even without your designware patch.
>
> Obviously, it won't make SR-IOV work, so we still need both patches.
Thanks, I'll provide patch in V2.
>
> Bjorn
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