From: Vitaly Kuznetsov <vkuzn...@redhat.com>

It may happen that secondary CPUs are still alive and resetting
hv_context.tsc_page will cause a consequent crash in read_hv_clock_tsc()
as we don't check for it being not NULL there. It is safe as we're not
freeing this page anyways.

Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
Cc: <sta...@vger.kernel.org>
---
 drivers/hv/hv.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index c11393c..60f14c4 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -309,9 +309,10 @@ void hv_cleanup(bool crash)
 
                hypercall_msr.as_uint64 = 0;
                wrmsrl(HV_X64_MSR_REFERENCE_TSC, hypercall_msr.as_uint64);
-               if (!crash)
+               if (!crash) {
                        vfree(hv_context.tsc_page);
-               hv_context.tsc_page = NULL;
+                       hv_context.tsc_page = NULL;
+               }
        }
 #endif
 }
-- 
1.7.4.1

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