* [EMAIL PROTECTED] ([EMAIL PROTECTED]) wrote: > ACPI uses NR_CPUS in various loops and in some it accesses per cpu > data of processors that are not present(!) and that will never be present. > The pointers to per cpu data are typically not initialized for processors > that are not present. So we seem to be reading something here from offset 0 > in memory. > > Make ACPI use nr_cpu_ids instead. That stops at the end of the possible > processors. > > Convert one loop to NR_CPUS to use the cpu_possible map instead. >
I'm just wondering how broken this is. Is there any assumption that there is no holes in the online cpu map in this code ? We can very well have : 0 off 1 on 2 on 3 on ... > Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]> > > --- > drivers/acpi/processor_core.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > Index: linux-2.6/drivers/acpi/processor_core.c > =================================================================== > --- linux-2.6.orig/drivers/acpi/processor_core.c 2007-11-19 > 15:45:05.041140492 -0800 > +++ linux-2.6/drivers/acpi/processor_core.c 2007-11-19 15:48:22.513639920 > -0800 > @@ -494,7 +494,7 @@ static int get_cpu_id(acpi_handle handle > if (apic_id == -1) > return apic_id; > > - for (i = 0; i < NR_CPUS; ++i) { > + for_each_possible_cpu(i) { > if (cpu_physical_id(i) == apic_id) > return i; > } > @@ -638,7 +638,7 @@ static int __cpuinit acpi_processor_star > return 0; > } > > - BUG_ON((pr->id >= NR_CPUS) || (pr->id < 0)); > + BUG_ON((pr->id >= nr_cpu_ids) || (pr->id < 0)); > > /* > * Buggy BIOS check > @@ -771,7 +771,7 @@ static int acpi_processor_remove(struct > > pr = acpi_driver_data(device); > > - if (pr->id >= NR_CPUS) { > + if (pr->id >= nr_cpu_ids) { > kfree(pr); > return 0; > } > @@ -842,7 +842,7 @@ int acpi_processor_device_add(acpi_handl > if (!pr) > return -ENODEV; > > - if ((pr->id >= 0) && (pr->id < NR_CPUS)) { > + if ((pr->id >= 0) && (pr->id < nr_cpu_ids)) { > kobject_uevent(&(*device)->dev.kobj, KOBJ_ONLINE); > } > return 0; > @@ -880,13 +880,13 @@ acpi_processor_hotplug_notify(acpi_handl > break; > } > > - if (pr->id >= 0 && (pr->id < NR_CPUS)) { > + if (pr->id >= 0 && (pr->id < nr_cpu_ids)) { > kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE); > break; > } > > result = acpi_processor_start(device); > - if ((!result) && ((pr->id >= 0) && (pr->id < NR_CPUS))) { > + if ((!result) && ((pr->id >= 0) && (pr->id < nr_cpu_ids))) { > kobject_uevent(&device->dev.kobj, KOBJ_ONLINE); > } else { > printk(KERN_ERR PREFIX "Device [%s] failed to start\n", > @@ -909,7 +909,7 @@ acpi_processor_hotplug_notify(acpi_handl > return; > } > > - if ((pr->id < NR_CPUS) && (cpu_present(pr->id))) > + if ((pr->id < nr_cpu_ids) && (cpu_present(pr->id))) > kobject_uevent(&device->dev.kobj, KOBJ_OFFLINE); > break; > default: > > -- -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/