From: Ryan Grimm Date: Thu, 29 Jan 2015 02:16:04 +0000 (-0600) Subject: cxl: Fix device_node reference counting X-Git-Tag: firefly_0821_release~176^2~2353^2~16 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6f963ec2d6bf2476a16799eece920acb2100ff1c;p=firefly-linux-kernel-4.4.55.git cxl: Fix device_node reference counting When unbinding and rebinding the driver on a system with a card in PHB0, this error condition is reached after a few attempts: ERROR: Bad of_node_put() on /pciex@3fffe40000000 CPU: 0 PID: 3040 Comm: bash Not tainted 3.18.0-rc3-12545-g3627ffe #152 Call Trace: [c000000721acb5c0] [c00000000086ef94] .dump_stack+0x84/0xb0 (unreliable) [c000000721acb640] [c00000000073a0a8] .of_node_release+0xd8/0xe0 [c000000721acb6d0] [c00000000044bc44] .kobject_release+0x74/0xe0 [c000000721acb760] [c0000000007394fc] .of_node_put+0x1c/0x30 [c000000721acb7d0] [c000000000545cd8] .cxl_probe+0x1a98/0x1d50 [c000000721acb900] [c0000000004845a0] .local_pci_probe+0x40/0xc0 [c000000721acb980] [c000000000484998] .pci_device_probe+0x128/0x170 [c000000721acba30] [c00000000052400c] .driver_probe_device+0xac/0x2a0 [c000000721acbad0] [c000000000522468] .bind_store+0x108/0x160 [c000000721acbb70] [c000000000521448] .drv_attr_store+0x38/0x60 [c000000721acbbe0] [c000000000293840] .sysfs_kf_write+0x60/0xa0 [c000000721acbc50] [c000000000292500] .kernfs_fop_write+0x140/0x1d0 [c000000721acbcf0] [c000000000208648] .vfs_write+0xd8/0x260 [c000000721acbd90] [c000000000208b18] .SyS_write+0x58/0x100 [c000000721acbe30] [c000000000009258] syscall_exit+0x0/0x98 We are missing a call to of_node_get(). pnv_pci_to_phb_node() should call of_node_get() otherwise np's reference count isn't incremented and it might go away. Rename pnv_pci_to_phb_node() to pnv_pci_get_phb_node() so it's clear it calls of_node_get(). Signed-off-by: Ryan Grimm Acked-by: Ian Munsie Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/include/asm/pnv-pci.h b/arch/powerpc/include/asm/pnv-pci.h index 3c00d648336d..f9b498292a5c 100644 --- a/arch/powerpc/include/asm/pnv-pci.h +++ b/arch/powerpc/include/asm/pnv-pci.h @@ -19,7 +19,7 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq, int pnv_cxl_alloc_hwirqs(struct pci_dev *dev, int num); void pnv_cxl_release_hwirqs(struct pci_dev *dev, int hwirq, int num); int pnv_cxl_get_irq_count(struct pci_dev *dev); -struct device_node *pnv_pci_to_phb_node(struct pci_dev *dev); +struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev); #ifdef CONFIG_CXL_BASE int pnv_cxl_alloc_hwirq_ranges(struct cxl_irq_ranges *irqs, diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index 85b473823fda..6c9ff2b95119 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -1487,13 +1487,13 @@ static void set_msi_irq_chip(struct pnv_phb *phb, unsigned int virq) #ifdef CONFIG_CXL_BASE -struct device_node *pnv_pci_to_phb_node(struct pci_dev *dev) +struct device_node *pnv_pci_get_phb_node(struct pci_dev *dev) { struct pci_controller *hose = pci_bus_to_host(dev->bus); - return hose->dn; + return of_node_get(hose->dn); } -EXPORT_SYMBOL(pnv_pci_to_phb_node); +EXPORT_SYMBOL(pnv_pci_get_phb_node); int pnv_phb_to_cxl_mode(struct pci_dev *dev, uint64_t mode) { diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index 428ea8ba25fc..cb250673b5c6 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -317,7 +317,7 @@ static int init_implementation_adapter_regs(struct cxl *adapter, struct pci_dev u64 psl_dsnctl; u64 chipid; - if (!(np = pnv_pci_to_phb_node(dev))) + if (!(np = pnv_pci_get_phb_node(dev))) return -ENODEV; while (np && !(prop = of_get_property(np, "ibm,chip-id", NULL)))