From e79018544d8e0e491f03c6a415632a49d0562379 Mon Sep 17 00:00:00 2001 From: Romain Naour Date: Wed, 22 Apr 2020 01:00:05 +0200 Subject: [PATCH] support/scripts/boot-qemu-image.py: wait before using expect As reported by a gitlab runtime test [1] and on the mailing list [2], some runtime tests are failing on slow host machines when the qemu-system- is missing on the host. The boot-qemu-image.py script need to wait some time after calling pexpect.spawn() in order to make sure that the qemu process has been executed in start-qemu.sh. If start-qemu.sh failed due to missing qemu-system binary an exception will be thrown by child.expect() and should be catched by the error handling (pexpect.EOF). After spending a lot of time to investigate with Yann E. MORIN [3]. It seems that short-lived child processes are a corner-case that is not very correctly handled... Without adding a sleep(1), child.expect() can trigger an exception before setting the exitstatus of the spawned process. This issue can be reproduced on a gitlab runner or by adding "exit 1" in the first line of start-qemu.sh (after the shebang). There is even the same workaround in some pexpect examples [4]. Thanks to Yann for the help while investigating the issue. Tested: https://gitlab.com/kubu93/buildroot/pipelines/138472925 [1] https://gitlab.com/kubu93/buildroot/pipelines/135487475 [2] http://lists.busybox.net/pipermail/buildroot/2020-April/280037.html [3] http://patchwork.ozlabs.org/project/buildroot/patch/20200418161023.1221799-1-romain.naour@gmail.com/ [4] https://github.com/pexpect/pexpect/blob/master/examples/ssh_tunnel.py#L80 Fixes: https://gitlab.com/kubu93/buildroot/-/jobs/509053135 Signed-off-by: Romain Naour Cc: Yann E. MORIN [yann.morin.1998@free.fr: reorder imports] Signed-off-by: Yann E. MORIN --- support/scripts/boot-qemu-image.py | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/support/scripts/boot-qemu-image.py b/support/scripts/boot-qemu-image.py index 2c1afba398..dbbba552ad 100755 --- a/support/scripts/boot-qemu-image.py +++ b/support/scripts/boot-qemu-image.py @@ -2,9 +2,10 @@ # This script expect to run from the Buildroot top directory. +import os import pexpect import sys -import os +import time def main(): @@ -26,6 +27,10 @@ def main(): # We want only stdout into the log to avoid double echo child.logfile = sys.stdout + # Let the spawn actually try to fork+exec to the wrapper, and then + # let the wrapper exec the qemu process. + time.sleep(1) + try: child.expect(["buildroot login:", pexpect.TIMEOUT], timeout=60) except pexpect.EOF as e: -- 2.30.2