[PATCH V2 04/13] Drivers: hv: vmbus: don't manipulate with clocksources on crash

K. Y. Srinivasan
2016-01-28T04:54:07Z

From: Vitaly Kuznetsov <vkuznets@redhat.com>

clocksource_change_rating() involves mutex usage and can't be called
in interrupt context. It also makes sense to avoid doing redundant work
on crash.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
drivers/hv/hv.c | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 11bca51..257de21 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -295,8 +295,14 @@ void hv_cleanup(void)
* Cleanup the TSC page based CS.
*/
if (ms_hyperv.features & HV_X64_MSR_REFERENCE_TSC_AVAILABLE) {
- clocksource_change_rating(&hyperv_cs_tsc, 10);
- clocksource_unregister(&hyperv_cs_tsc);
+ /*
+ * Crash can happen in an interrupt context and unregistering
+ * a clocksource is impossible and redundant in this case.
+ */
+ if (!oops_in_progress) {
+ clocksource_change_rating(&hyperv_cs_tsc, 10);
+ clocksource_unregister(&hyperv_cs_tsc);
+ }

hypercall_msr.as_uint64 = 0;
wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
--
1.7.4.1