From ffdec41922a34b6fe4e7e11f259553d65b41563e Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 11 Jan 2022 15:36:13 +0000 Subject: [PATCH 4/6] iotests/stream-error-on-reset: New test RH-Author: Stefan Hajnoczi RH-MergeRequest: 109: block-backend: prevent dangling BDS pointers across aio_poll() RH-Commit: [2/2] 0ecb7010d9c121398e7ee22ee47dd85d89bcd941 RH-Bugzilla: 2021778 2036178 RH-Acked-by: Hanna Reitz RH-Acked-by: Emanuele Giuseppe Esposito RH-Acked-by: Kevin Wolf Author: Hanna Reitz Test the following scenario: - Simple stream block in two-layer backing chain (base and top) - The job is drained via blk_drain(), then an error occurs while the job settles the ongoing request - And so the job completes while in blk_drain() This was reported as a segfault, but is fixed by "block-backend: prevent dangling BDS pointers across aio_poll()". Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2036178 Signed-off-by: Hanna Reitz Signed-off-by: Stefan Hajnoczi Message-Id: <20220111153613.25453-3-stefanha@redhat.com> Signed-off-by: Kevin Wolf (cherry picked from commit 2ca1d5d6b91f8a52a5c651f660b2f58c94bf97ba) Signed-off-by: Stefan Hajnoczi --- .../qemu-iotests/tests/stream-error-on-reset | 140 ++++++++++++++++++ .../tests/stream-error-on-reset.out | 5 + 2 files changed, 145 insertions(+) create mode 100755 tests/qemu-iotests/tests/stream-error-on-reset create mode 100644 tests/qemu-iotests/tests/stream-error-on-reset.out diff --git a/tests/qemu-iotests/tests/stream-error-on-reset b/tests/qemu-iotests/tests/stream-error-on-reset new file mode 100755 index 0000000000..7eaedb24d7 --- /dev/null +++ b/tests/qemu-iotests/tests/stream-error-on-reset @@ -0,0 +1,140 @@ +#!/usr/bin/env python3 +# group: rw quick +# +# Test what happens when a stream job completes in a blk_drain(). +# +# Copyright (C) 2022 Red Hat, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# + +import os +import iotests +from iotests import imgfmt, qemu_img_create, qemu_io_silent, QMPTestCase + + +image_size = 1 * 1024 * 1024 +data_size = 64 * 1024 +base = os.path.join(iotests.test_dir, 'base.img') +top = os.path.join(iotests.test_dir, 'top.img') + + +# We want to test completing a stream job in a blk_drain(). +# +# The blk_drain() we are going to use is a virtio-scsi device resetting, +# which we can trigger by resetting the system. +# +# In order to have the block job complete on drain, we (1) throttle its +# base image so we can start the drain after it has begun, but before it +# completes, and (2) make it encounter an I/O error on the ensuing write. +# (If it completes regularly, the completion happens after the drain for +# some reason.) + +class TestStreamErrorOnReset(QMPTestCase): + def setUp(self) -> None: + """ + Create two images: + - base image {base} with {data_size} bytes allocated + - top image {top} without any data allocated + + And the following VM configuration: + - base image throttled to {data_size} + - top image with a blkdebug configuration so the first write access + to it will result in an error + - top image is attached to a virtio-scsi device + """ + assert qemu_img_create('-f', imgfmt, base, str(image_size)) == 0 + assert qemu_io_silent('-c', f'write 0 {data_size}', base) == 0 + assert qemu_img_create('-f', imgfmt, top, str(image_size)) == 0 + + self.vm = iotests.VM() + self.vm.add_args('-accel', 'tcg') # Make throttling work properly + self.vm.add_object(self.vm.qmp_to_opts({ + 'qom-type': 'throttle-group', + 'id': 'thrgr', + 'x-bps-total': str(data_size) + })) + self.vm.add_blockdev(self.vm.qmp_to_opts({ + 'driver': imgfmt, + 'node-name': 'base', + 'file': { + 'driver': 'throttle', + 'throttle-group': 'thrgr', + 'file': { + 'driver': 'file', + 'filename': base + } + } + })) + self.vm.add_blockdev(self.vm.qmp_to_opts({ + 'driver': imgfmt, + 'node-name': 'top', + 'file': { + 'driver': 'blkdebug', + 'node-name': 'top-blkdebug', + 'inject-error': [{ + 'event': 'pwritev', + 'immediately': 'true', + 'once': 'true' + }], + 'image': { + 'driver': 'file', + 'filename': top + } + }, + 'backing': 'base' + })) + self.vm.add_device(self.vm.qmp_to_opts({ + 'driver': 'virtio-scsi', + 'id': 'vscsi' + })) + self.vm.add_device(self.vm.qmp_to_opts({ + 'driver': 'scsi-hd', + 'bus': 'vscsi.0', + 'drive': 'top' + })) + self.vm.launch() + + def tearDown(self) -> None: + self.vm.shutdown() + os.remove(top) + os.remove(base) + + def test_stream_error_on_reset(self) -> None: + # Launch a stream job, which will take at least a second to + # complete, because the base image is throttled (so we can + # get in between it having started and it having completed) + res = self.vm.qmp('block-stream', job_id='stream', device='top') + self.assert_qmp(res, 'return', {}) + + while True: + ev = self.vm.event_wait('JOB_STATUS_CHANGE') + if ev['data']['status'] == 'running': + # Once the stream job is running, reset the system, which + # forces the virtio-scsi device to be reset, thus draining + # the stream job, and making it complete. Completing + # inside of that drain should not result in a segfault. + res = self.vm.qmp('system_reset') + self.assert_qmp(res, 'return', {}) + elif ev['data']['status'] == 'null': + # The test is done once the job is gone + break + + +if __name__ == '__main__': + # Passes with any format with backing file support, but qed and + # qcow1 do not seem to exercise the used-to-be problematic code + # path, so there is no point in having them in this list + iotests.main(supported_fmts=['qcow2', 'vmdk'], + supported_protocols=['file']) diff --git a/tests/qemu-iotests/tests/stream-error-on-reset.out b/tests/qemu-iotests/tests/stream-error-on-reset.out new file mode 100644 index 0000000000..ae1213e6f8 --- /dev/null +++ b/tests/qemu-iotests/tests/stream-error-on-reset.out @@ -0,0 +1,5 @@ +. +---------------------------------------------------------------------- +Ran 1 tests + +OK -- 2.27.0