[OE-core] [PATCH 1/3] qemurunner.py: fix is_alive() to avoid confusing with recycled pid

[Robert Yang]

[YOCTO #12493]

Fixed:
- qemu started with pid 10000
- qemu exited unexpectedly
- The pid 10000 is re-used by another different process.

The is_alive() returned True in such a case because both qemu_pidfile and
/proc/10000 exist, but it's another process, this patch fixed the problem.

Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 meta/lib/oeqa/utils/qemurunner.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/meta/lib/oeqa/utils/qemurunner.py b/meta/lib/oeqa/utils/qemurunner.py
index c962602..864fc71 100644
--- a/meta/lib/oeqa/utils/qemurunner.py
+++ b/meta/lib/oeqa/utils/qemurunner.py
@@ -400,7 +400,7 @@ class QemuRunner:
         return False
 
     def is_alive(self):
-        if not self.runqemu:
+        if not self.runqemu or self.runqemu.poll() is not None:
             return False
         if os.path.isfile(self.qemu_pidfile):
             f = open(self.qemu_pidfile, 'r')
-- 
2.7.4