See http://bugs.centos.org/view.php?id=4139
and http://bugs.centos.org/view.php?id=4100
for details

Try this patch, which I backported to RHEL5.4. Didn't build test
or anything.

Let me know how much further you get.

To limit the amount of oops output you get, try playing with the
kstack=N kerneld command line parameter.

/ac

diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
index 9e8d010..3394d11 100644
--- a/drivers/acpi/Makefile
+++ b/drivers/acpi/Makefile
@@ -59,6 +59,7 @@
 obj-$(CONFIG_ACPI_IBM)		+= ibm_acpi.o
 obj-$(CONFIG_ACPI_TOSHIBA)	+= toshiba_acpi.o
 obj-y				+= scan.o motherboard.o
+obj-y				+= processor_pdc.o
 obj-$(CONFIG_ACPI_HOTPLUG_MEMORY)	+= acpi_memhotplug.o
 obj-y				+= cm_sbs.o
 obj-$(CONFIG_ACPI_SBS)		+= i2c_ec.o sbs.o
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -701,6 +701,8 @@
 		goto error1;
 	}
 
+	acpi_early_processor_set_pdc();
+
 	printk(KERN_INFO PREFIX "Interpreter enabled\n");
 
 	/*
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c

@@ -244,31 +244,6 @@
 	return result;
 }
 
-/* --------------------------------------------------------------------------
-                              Common ACPI processor functions
-   -------------------------------------------------------------------------- */
-
-/*
- * _PDC is required for a BIOS-OS handshake for most of the newer
- * ACPI processor features.
- */
-static int acpi_processor_set_pdc(struct acpi_processor *pr)
-{
-	struct acpi_object_list *pdc_in = pr->pdc;
-	acpi_status status = AE_OK;
-
-
-	if (!pdc_in)
-		return status;
-
-	status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
-
-	if (ACPI_FAILURE(status))
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-		    "Could not evaluate _PDC, using legacy perf. control...\n"));
-
-	return status;
-}
 
 /* --------------------------------------------------------------------------
                               FS Interface (/proc)
@@ -568,7 +543,6 @@
 					     acpi_processor_notify, pr);
 
 	/* _PDC call should be done before doing anything else (if reqd.). */
-	arch_acpi_processor_init_pdc(pr);
 	acpi_processor_set_pdc(pr);
 
 	acpi_processor_power_init(pr, device);
                               FS Interface (/proc)
diff --git a/drivers/acpi/processor_pdc.c b/drivers/acpi/processor_pdc.c
new file mode 100644
--- /dev/null
+++ b/drivers/acpi/processor_pdc.c
@@ -0,0 +1,60 @@
+#include <acpi/acpi_drivers.h>
+#include <acpi/processor.h>
+
+#define PREFIX			"ACPI: "
+#define _COMPONENT		ACPI_PROCESSOR_COMPONENT
+ACPI_MODULE_NAME("processor_pdc");
+
+/*
+ * _PDC is required for a BIOS-OS handshake for most of the newer
+ * ACPI processor features.
+ */
+static int acpi_processor_eval_pdc(struct acpi_processor *pr)
+{
+	struct acpi_object_list *pdc_in = pr->pdc;
+	acpi_status status = AE_OK;
+
+	if (!pdc_in)
+		return status;
+
+	status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
+
+	if (ACPI_FAILURE(status))
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+		    "Could not evaluate _PDC, using legacy perf. control.\n"));
+
+	return status;
+}
+
+void acpi_processor_set_pdc(struct acpi_processor *pr)
+{
+	arch_acpi_processor_init_pdc(pr);
+	acpi_processor_eval_pdc(pr);
+}
+EXPORT_SYMBOL_GPL(acpi_processor_set_pdc);
+
+static acpi_status
+early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	struct acpi_processor pr;
+
+	pr.handle = handle;
+
+	/* x86 implementation looks at pr.id to determine some
+	 * CPU capabilites. We can just hard code to 0 since we're
+	 * assuming the CPUs in the system are homogenous and all
+	 * have the same capabilities.
+	 */
+	pr.id = 0;
+
+	acpi_processor_set_pdc(&pr);
+
+	return AE_OK;
+}
+
+void acpi_early_processor_set_pdc(void)
+{
+	acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
+			    ACPI_UINT32_MAX,
+			    early_init_pdc, NULL, NULL);
+}
diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index 588c456..055bb61 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -87,6 +87,8 @@
 int acpi_power_transition(struct acpi_device *device, int state);
 #endif
 
+void acpi_early_processor_set_pdc(void);
+
 /* --------------------------------------------------------------------------
                                   Embedded Controller
    -------------------------------------------------------------------------- */
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -288,6 +288,9 @@
 }
 #endif				/* CONFIG_CPU_FREQ */
 
+/* in processor_pdc.c */
+void acpi_processor_set_pdc(struct acpi_processor *pr);
+
 /* in processor_throttling.c */
 int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
 int acpi_processor_get_throttling_info(struct acpi_processor *pr);