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* [PATCH] hv: don't reset hv_context.tsc_page on crash
@ 2016-11-30 18:14 Vitaly Kuznetsov
  0 siblings, 0 replies; only message in thread
From: Vitaly Kuznetsov @ 2016-11-30 18:14 UTC (permalink / raw)
  To: devel; +Cc: linux-kernel, K. Y. Srinivasan, Haiyang Zhang

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>
---
 drivers/hv/hv.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 60dbd6c..f4b4e2e 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
 }
-- 
2.9.3

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2016-11-30 18:14 [PATCH] hv: don't reset hv_context.tsc_page on crash Vitaly Kuznetsov

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