From 842721581fdbed45fa4738d02df8d28b1eaf28dd Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 4 Mar 2025 18:33:40 +0000 Subject: [PATCH] tests/functional: fix race in virtio balloon test MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit There are two race conditions in the recently added virtio balloon test * The /dev/vda device node is not ready * The virtio-balloon driver has not issued the first stats refresh To fix the former, monitor dmesg for a line about 'vda'. To fix the latter, retry the stats query until seeing fresh data. Adding 'quiet' to the kernel command line reduces serial output which otherwise slows boot, making it less likely to hit the former race too. Signed-off-by: Daniel P. Berrangé Message-ID: <20250304183340.3749797-1-berrange@redhat.com> Reviewed-by: Thomas Huth Reviewed-by: David Hildenbrand [thuth: Break long line to avoid checkpatch error] Signed-off-by: Thomas Huth --- tests/functional/test_virtio_balloon.py | 26 ++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-) diff --git a/tests/functional/test_virtio_balloon.py b/tests/functional/test_virtio_balloon.py index 67b48e1b4e..082bf08c4e 100755 --- a/tests/functional/test_virtio_balloon.py +++ b/tests/functional/test_virtio_balloon.py @@ -32,7 +32,7 @@ class VirtioBalloonx86(QemuSystemTest): 'e3c1b309d9203604922d6e255c2c5d098a309c2d46215d8fc026954f3c5c27a0') DEFAULT_KERNEL_PARAMS = ('root=/dev/vda1 console=ttyS0 net.ifnames=0 ' - 'rd.rescue') + 'rd.rescue quiet') def wait_for_console_pattern(self, success_message, vm=None): wait_for_console_pattern( @@ -47,6 +47,11 @@ class VirtioBalloonx86(QemuSystemTest): prompt = '# ' self.wait_for_console_pattern(prompt) + # Synchronize on virtio-block driver creating the root device + exec_command_and_wait_for_pattern(self, + "while ! (dmesg -c | grep vda:) ; do sleep 1 ; done", + "vda1") + exec_command_and_wait_for_pattern(self, 'mount /dev/vda1 /sysroot', prompt) exec_command_and_wait_for_pattern(self, 'chroot /sysroot', @@ -65,10 +70,21 @@ class VirtioBalloonx86(QemuSystemTest): assert val == UNSET_STATS_VALUE def assert_running_stats(self, then): - ret = self.vm.qmp('qom-get', - {'path': '/machine/peripheral/balloon', - 'property': 'guest-stats'})['return'] - when = ret.get('last-update') + # We told the QEMU to refresh stats every 100ms, but + # there can be a delay between virtio-ballon driver + # being modprobed and seeing the first stats refresh + # Retry a few times for robustness under heavy load + retries = 10 + when = 0 + while when == 0 and retries: + ret = self.vm.qmp('qom-get', + {'path': '/machine/peripheral/balloon', + 'property': 'guest-stats'})['return'] + when = ret.get('last-update') + if when == 0: + retries = retries - 1 + time.sleep(0.5) + now = time.time() assert when > then and when < now -- 2.39.5