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Groups > linux.kernel > #1537575

[PATCH 4/5] hv: don't reset hv_context.tsc_page on crash

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From: Vitaly Kuznetsov <vkuznets@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 <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: <stable@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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[PATCH 0/5] Drivers: hv: vmbus: Some miscellaneous fixes  kys@exchange.microsoft.com - 2016-12-07 08:30 +0100
  [PATCH 4/5] hv: don't reset hv_context.tsc_page on crash kys@exchange.microsoft.com - 2016-12-07 08:40 +0100
  [PATCH 2/5] hv: allocate synic pages for all present CPUs kys@exchange.microsoft.com - 2016-12-07 08:40 +0100
  [PATCH 3/5] hv: init percpu_list in hv_synic_alloc() kys@exchange.microsoft.com - 2016-12-07 08:40 +0100
  [PATCH 5/5] Drivers: hv: vmbus: Prevent sending data on a rescinded channel kys@exchange.microsoft.com - 2016-12-07 08:40 +0100
  [PATCH 1/5] Drivers: hv: vmbus: Raise retry/wait limits in vmbus_post_msg() kys@exchange.microsoft.com - 2016-12-07 08:40 +0100

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