We noticed this panic while enabling SR-IOV in sparc. mlx4_core: Mellanox ConnectX core driver v2.2-1 (Jan 1 2015) mlx4_core: Initializing 0007:01:00.0 mlx4_core 0007:01:00.0: Enabling SR-IOV with 5 VFs mlx4_core: Initializing 0007:01:00.1 Unable to handle kernel NULL pointer dereference insmod(10010): Oops [#1] CPU: 391 PID: 10010 Comm: insmod Not tainted 4.1.12-32.el6uek.kdump2.sparc64 #1 TPC: <dma_supported+0x20/0x80> I7: <__mlx4_init_one+0x324/0x500 [mlx4_core]> Call Trace: [00000000104c5ea4] __mlx4_init_one+0x324/0x500 [mlx4_core] [00000000104c613c] mlx4_init_one+0xbc/0x120 [mlx4_core] [0000000000725f14] local_pci_probe+0x34/0xa0 [0000000000726028] pci_call_probe+0xa8/0xe0 [0000000000726310] pci_device_probe+0x50/0x80 [000000000079f700] really_probe+0x140/0x420 [000000000079fa24] driver_probe_device+0x44/0xa0 [000000000079fb5c] __device_attach+0x3c/0x60 [000000000079d85c] bus_for_each_drv+0x5c/0xa0 [000000000079f588] device_attach+0x88/0xc0 [000000000071acd0] pci_bus_add_device+0x30/0x80 [0000000000736090] virtfn_add.clone.1+0x210/0x360 [00000000007364a4] sriov_enable+0x2c4/0x520 [000000000073672c] pci_enable_sriov+0x2c/0x40 [00000000104c2d58] mlx4_enable_sriov+0xf8/0x180 [mlx4_core] [00000000104c49ac] mlx4_load_one+0x42c/0xd40 [mlx4_core] Disabling lock debugging due to kernel taint Caller[00000000104c5ea4]: __mlx4_init_one+0x324/0x500 [mlx4_core] Caller[00000000104c613c]: mlx4_init_one+0xbc/0x120 [mlx4_core] Caller[0000000000725f14]: local_pci_probe+0x34/0xa0 Caller[0000000000726028]: pci_call_probe+0xa8/0xe0 Caller[0000000000726310]: pci_device_probe+0x50/0x80 Caller[000000000079f700]: really_probe+0x140/0x420 Caller[000000000079fa24]: driver_probe_device+0x44/0xa0 Caller[000000000079fb5c]: __device_attach+0x3c/0x60 Caller[000000000079d85c]: bus_for_each_drv+0x5c/0xa0 Caller[000000000079f588]: device_attach+0x88/0xc0 Caller[000000000071acd0]: pci_bus_add_device+0x30/0x80 Caller[0000000000736090]: virtfn_add.clone.1+0x210/0x360 Caller[00000000007364a4]: sriov_enable+0x2c4/0x520 Caller[000000000073672c]: pci_enable_sriov+0x2c/0x40 Caller[00000000104c2d58]: mlx4_enable_sriov+0xf8/0x180 [mlx4_core] Caller[00000000104c49ac]: mlx4_load_one+0x42c/0xd40 [mlx4_core] Caller[00000000104c5f90]: __mlx4_init_one+0x410/0x500 [mlx4_core] Caller[00000000104c613c]: mlx4_init_one+0xbc/0x120 [mlx4_core] Caller[0000000000725f14]: local_pci_probe+0x34/0xa0 Caller[0000000000726028]: pci_call_probe+0xa8/0xe0 Caller[0000000000726310]: pci_device_probe+0x50/0x80 Caller[000000000079f700]: really_probe+0x140/0x420 Caller[000000000079fa24]: driver_probe_device+0x44/0xa0 Caller[000000000079fb08]: __driver_attach+0x88/0xa0 Caller[000000000079d90c]: bus_for_each_dev+0x6c/0xa0 Caller[000000000079f29c]: driver_attach+0x1c/0x40 Caller[000000000079e35c]: bus_add_driver+0x17c/0x220 Caller[00000000007a02d4]: driver_register+0x74/0x120 Caller[00000000007263fc]: __pci_register_driver+0x3c/0x60 Caller[00000000104f62bc]: mlx4_init+0x60/0xcc [mlx4_core] Kernel panic - not syncing: Fatal exception Press Stop-A (L1-A) to return to the boot prom ---[ end Kernel panic - not syncing: Fatal exception
Details: Here is the call sequence virtfn_add->__mlx4_init_one->dma_set_mask->dma_supported The panic happened at line 760(file arch/sparc/kernel/iommu.c) 758 int dma_supported(struct device *dev, u64 device_mask) 759 { 760 struct iommu *iommu = dev->archdata.iommu; 761 u64 dma_addr_mask = iommu->dma_addr_mask; 762 763 if (device_mask >= (1UL << 32UL)) 764 return 0; 765 766 if ((device_mask & dma_addr_mask) == dma_addr_mask) 767 return 1; 768 769 #ifdef CONFIG_PCI 770 if (dev_is_pci(dev)) 771 return pci64_dma_supported(to_pci_dev(dev), device_mask); 772 #endif 773 774 return 0; 775 } 776 EXPORT_SYMBOL(dma_supported); Same panic happened with Intel ixgbe driver also. SR-IOV code looks for arch specific data while enabling VFs. When VF device is added, driver probe function makes set of calls to initialize the pci device. Because the VF device is added different way than the normal PF device(which happens via of_create_pci_dev for sparc), some of the arch specific initialization does not happen for VF device. That causes panic when archdata is accessed. To fix this, I have used already defined weak function pcibios_setup_device to copy archdata from PF to VF. Also verified the fix. Signed-off-by: Babu Moger <babu.mo...@oracle.com> Signed-off-by: Sowmini Varadhan <sowmini.varad...@oracle.com> Reviewed-by: Ethan Zhao <ethan.z...@oracle.com> --- v2: Removed RFC. Made changes per comments from Ethan Zhao. Now the changes are only in Sparc specific code. Removed the changes from driver/pci. Implemented already defined weak function pcibios_add_device in arch/sparc/kernel/pci.c to initialize sriov archdata. arch/sparc/kernel/pci.c | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c index badf095..7749b65 100644 --- a/arch/sparc/kernel/pci.c +++ b/arch/sparc/kernel/pci.c @@ -994,6 +994,21 @@ void pcibios_set_master(struct pci_dev *dev) /* No special bus mastering setup handling */ } +int pcibios_add_device(struct pci_dev *dev) +{ + struct pci_dev *pdev; + /* + * Add sriov arch specific initialization here. + * Copy dev_archdata from PF to VF + */ + if (dev->is_virtfn) { + pdev = dev->physfn; + memcpy(&dev->dev.archdata, &pdev->dev.archdata, + sizeof(struct dev_archdata)); + } + return 0; +} + static int __init pcibios_init(void) { pci_dfl_cache_line_size = 64 >> 2; -- 1.7.1