xen: print backtrace on multicall failure

Print a backtrace if a multicall fails, to help with debugging.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/xen/multicalls.c b/arch/x86/xen/multicalls.c
index 3c63c4da7ed1..9efd1c6c9776 100644
--- a/arch/x86/xen/multicalls.c
+++ b/arch/x86/xen/multicalls.c
@@ -76,6 +76,7 @@ void xen_mc_flush(void)
                 if (ret) {
                         printk(KERN_ERR "%d multicall(s) failed: cpu %d\n",
                                ret, smp_processor_id());
+                        dump_stack();
                         for (i = 0; i < b->mcidx; i++) {
                                 printk("  call %2d/%d: op=%lu arg=[%lx] result=%ld\n",
                                        i+1, b->mcidx,