Patch "hv: don't reset hv_context.tsc_page on crash" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

hv: don't reset hv_context.tsc_page on crash

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
hv-don-t-reset-hv_context.tsc_page-on-crash.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Vitaly Kuznetsov <[email protected]>
Date: Wed, 7 Dec 2016 01:16:27 -0800
Subject: hv: don't reset hv_context.tsc_page on crash

From: Vitaly Kuznetsov <[email protected]>

commit 56ef6718a1d8d77745033c5291e025ce18504159 upstream.

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.

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

@@ -305,9 +305,10 @@ 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
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drivers-hv-balloon-keep-track-of-where-ha_region-starts.patch queue-4.4/drivers-hv-get-rid-of-timeout-in-vmbus_open.patch queue-4.4/hv-don-t-reset-hv_context.tsc_page-on-crash.patch queue-4.4/drivers-hv-don-t-leak-memory-in-vmbus_establish_gpadl.patch queue-4.4/tools-hv-kvp-ensure-kvp-device-fd-is-closed-on-exec.patch queue-4.4/drivers-hv-balloon-account-for-gaps-in-hot-add-regions.patch