[PATCH 12/15] hv: don't reset hv_context.tsc_page on crash

From	kys@exchange.microsoft.com
Newsgroups	linux.kernel
Subject	[PATCH 12/15] hv: don't reset hv_context.tsc_page on crash
Date	2016-12-01 16:40 +0100
Message-ID	<sJBCO-5Lz-31@gated-at.bofh.it> (permalink)
References	<sJBCN-5Lz-9@gated-at.bofh.it> <sJBCN-5Lz-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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>
---
 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 4ece040..04a0fd8 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 12/15] hv: don't reset hv_context.tsc_page on crash kys@exchange.microsoft.com - 2016-12-01 16:40 +0100

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