On Thu, Aug 25, 2016 at 04:53:19AM +0000, Po Liu wrote: > > -----Original Message----- > > From: Bjorn Helgaas [mailto:helgaas@xxxxxxxxxx] > > Sent: Thursday, August 25, 2016 4:51 AM > > To: Po Liu > > Cc: linux-pci@xxxxxxxxxxxxxxx; Roy Zang; Arnd Bergmann; Stuart Yoder; > > Yang-Leo Li; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; 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@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@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. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
