#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt #include #include #include #include #include static void enable_hotplug_cpu(int cpu) { if (!cpu_present(cpu)) xen_arch_register_cpu(cpu); set_cpu_present(cpu, true); } static void disable_hotplug_cpu(int cpu) { if (cpu_online(cpu)) { lock_device_hotplug(); device_offline(get_cpu_device(cpu)); unlock_device_hotplug(); } if (cpu_present(cpu)) xen_arch_unregister_cpu(cpu); set_cpu_present(cpu, false); } static int vcpu_online(unsigned int cpu) { int err; char dir[16], state[16]; sprintf(dir, "cpu/%u", cpu); err = xenbus_scanf(XBT_NIL, dir, "availability", "%15s", state); if (err != 1) { if (!xen_initial_domain()) pr_err("Unable to read cpu state\n"); return err; } if (strcmp(state, "online") == 0) return 1; else if (strcmp(state, "offline") == 0) return 0; pr_err("unknown state(%s) on CPU%d\n", state, cpu); return -EINVAL; } static void vcpu_hotplug(unsigned int cpu) { if (!cpu_possible(cpu)) return; switch (vcpu_online(cpu)) { case 1: enable_hotplug_cpu(cpu); break; case 0: disable_hotplug_cpu(cpu); break; default: break; } } static void handle_vcpu_hotplug_event(struct xenbus_watch *watch, const char **vec, unsigned int len) { unsigned int cpu; char *cpustr; const char *node = vec[XS_WATCH_PATH]; cpustr = strstr(node, "cpu/"); if (cpustr != NULL) { sscanf(cpustr, "cpu/%u", &cpu); vcpu_hotplug(cpu); } } static int setup_cpu_watcher(struct notifier_block *notifier, unsigned long event, void *data) { int cpu; static struct xenbus_watch cpu_watch = { .node = "cpu", .callback = handle_vcpu_hotplug_event}; (void)register_xenbus_watch(&cpu_watch); for_each_possible_cpu(cpu) { if (vcpu_online(cpu) == 0) { (void)cpu_down(cpu); set_cpu_present(cpu, false); } } return NOTIFY_DONE; } static int __init setup_vcpu_hotplug_event(void) { static struct notifier_block xsn_cpu = { .notifier_call = setup_cpu_watcher }; #ifdef CONFIG_X86 if (!xen_pv_domain()) #else if (!xen_domain()) #endif return -ENODEV; register_xenstore_notifier(&xsn_cpu); return 0; } arch_initcall(setup_vcpu_hotplug_event); s-private-remove&id=030305d69fc6963c16003f50d7e8d74b02d0a143'>diff
path: root/drivers/usb/serial/qcserial.c
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authorBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
committerBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
commit030305d69fc6963c16003f50d7e8d74b02d0a143 (patch)
tree363a4e34d199178769b7e7eeb26ea2620a55847b /drivers/usb/serial/qcserial.c
parent4d191b1b63c209e37bf27938ef365244d3c41084 (diff)
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
In a struct pcie_link_state, link->root points to the pcie_link_state of the root of the PCIe hierarchy. For the topmost link, this points to itself (link->root = link). For others, we copy the pointer from the parent (link->root = link->parent->root). Previously we recognized that Root Ports originated PCIe hierarchies, but we treated PCI/PCI-X to PCIe Bridges as being in the middle of the hierarchy, and when we tried to copy the pointer from link->parent->root, there was no parent, and we dereferenced a NULL pointer: BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820 Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just like Root Ports do, so link->root for these devices should also point to itself. Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges") Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411 Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181 Tested-by: lists@ssl-mail.com Tested-by: Jayachandran C. <jnair@caviumnetworks.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v4.2+
Diffstat (limited to 'drivers/usb/serial/qcserial.c')