[Crash-utility] [PATCH] Change the way of determining the Xen scheduler

[Petr Tesarik]

The command line options (such as opt_sched) are discarded after boot in Xen4, 
so they are no longer available. Use the "ops" variable (if exists) to 
determine the active scheduler. Without this patch, crash fails during 
initialization on Xen4 hypervisor dumps with 'crash: schedule data not 
found.'

Signed-off-by: Petr Tesarik <ptesarik at suse.cz>
---
 xen_hyper.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/xen_hyper.c
+++ b/xen_hyper.c
@@ -445,13 +445,21 @@ xen_hyper_schedule_init(void)
 		error(FATAL, "cannot malloc scheduler struct space.\n");
 	}
 	buf = GETBUF(XEN_HYPER_SCHEDULER_NAME);	
-	opt_sched = symbol_value("opt_sched");
+	scheduler_opt_name = XEN_HYPER_OFFSET(scheduler_opt_name);
+	if (symbol_exists("ops")) {
+		if (!readmem(symbol_value("ops") + scheduler_opt_name, KVADDR,
+			&opt_sched, sizeof(ulong), "ops.opt_name",
+			RETURN_ON_ERROR)) {
+			error(FATAL, "cannot read ops.opt_name.\n");
+		}
+	} else {
+		opt_sched = symbol_value("opt_sched");
+	}
 	if (!readmem(opt_sched, KVADDR, xhscht->opt_sched,
 	XEN_HYPER_OPT_SCHED_SIZE, "opt_sched,", RETURN_ON_ERROR)) {
 		error(FATAL, "cannot read opt_sched,.\n");
 	}
 	schedulers = symbol_value("schedulers");
-	scheduler_opt_name = XEN_HYPER_OFFSET(scheduler_opt_name);
 	addr = schedulers;
 	while (xhscht->name == NULL) {
 		if (!readmem(addr, KVADDR, schedulers_buf,