From e0561198741b0d3a155924eca353bf7598534ca4 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Thu, 27 May 2010 13:37:55 +0200
Subject: [PATCH] Fix two race conditions in reboot instance
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If the instance crashes between backend.InstanceReboot checks the list
of running instances and the execution of hv_xen.RebootInstance,
ini_info will be None. And if the instance doesn't reboot fast enough,
new_info will be None. Both cases lead to βTypeError: unsubscriptable
objectβ. Too bad pylint doesn't detect such cases.
Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>
---
lib/hypervisor/hv_xen.py | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/lib/hypervisor/hv_xen.py b/lib/hypervisor/hv_xen.py
index a281e6a9b..77f98b079 100644
--- a/lib/hypervisor/hv_xen.py
+++ b/lib/hypervisor/hv_xen.py
@@ -213,6 +213,10 @@ class XenHypervisor(hv_base.BaseHypervisor):
"""
ini_info = self.GetInstanceInfo(instance.name)
+ if ini_info is None:
+ raise errors.HypervisorError("Failed to reboot instance %s,"
+ " not running" % instance.name)
+
result = utils.RunCmd(["xm", "reboot", instance.name])
if result.failed:
raise errors.HypervisorError("Failed to reboot instance %s: %s, %s" %
@@ -223,7 +227,8 @@ class XenHypervisor(hv_base.BaseHypervisor):
new_info = self.GetInstanceInfo(instance.name)
# check if the domain ID has changed or the run time has decreased
- if new_info[1] != ini_info[1] or new_info[5] < ini_info[5]:
+ if (new_info is not None and
+ (new_info[1] != ini_info[1] or new_info[5] < ini_info[5])):
return
raise utils.RetryAgain()
--
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