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* Fri Sep 27 2019 Danilo Cesar Lemes de Paula <ddepaula@redhat.com> - 4.1.0-13.el8

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- kvm-nbd-server-attach-client-channel-to-the-export-s-Aio.patch [bz#1748253]
- kvm-virtio-blk-schedule-virtio_notify_config-to-run-on-m.patch [bz#1744955]
- Resolves: bz#1744955
  (Qemu hang when block resize a qcow2 image)
- Resolves: bz#1748253
  (QEMU crashes (core dump) when using the integrated NDB server with data-plane)
This commit is contained in:
Danilo C. L. de Paula 2019-09-27 18:09:27 +01:00
parent 4172d6971a
commit 1eb8acbee7
3 changed files with 164 additions and 1 deletions
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60
kvm-nbd-server-attach-client-channel-to-the-export-s-Aio.patch Normal file
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@ -0,0 +1,60 @@
From 394dd52ce4dbd69cd5eca9a9928c442650cc3fd2 Mon Sep 17 00:00:00 2001
From: Sergio Lopez Pascual <slp@redhat.com>
Date: Fri, 27 Sep 2019 11:13:24 +0100
Subject: [PATCH 1/2] nbd/server: attach client channel to the export's
AioContext
RH-Author: Sergio Lopez Pascual <slp@redhat.com>
Message-id: <20190927111324.17949-2-slp@redhat.com>
Patchwork-id: 90905
O-Subject: [RHEL-AV-8.1.0 qemu-kvm PATCH 1/1] nbd/server: attach client channel to the export's AioContext
Bugzilla: 1748253
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Stefano Garzarella <sgarzare@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
On creation, the export's AioContext is set to the same one as the
BlockBackend, while the AioContext in the client QIOChannel is left
untouched.
As a result, when using data-plane, nbd_client_receive_next_request()
schedules coroutines in the IOThread AioContext, while the client's
QIOChannel is serviced from the main_loop, potentially triggering the
assertion at qio_channel_restart_[read|write].
To fix this, as soon we have the export corresponding to the client,
we call qio_channel_attach_aio_context() to attach the QIOChannel
context to the export's AioContext. This matches with the logic at
blk_aio_attached().
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1748253
Signed-off-by: Sergio Lopez <slp@redhat.com>
Message-Id: <20190912110032.26395-1-slp@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit b4961249af0403fa55aae57c4c8806b24f7a7b33)
Signed-off-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
nbd/server.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/nbd/server.c b/nbd/server.c
index 10faedc..ea0353a 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -1296,6 +1296,11 @@ static coroutine_fn int nbd_negotiate(NBDClient *client, Error **errp)
return ret;
}
+ /* Attach the channel to the same AioContext as the export */
+ if (client->exp && client->exp->ctx) {
+ qio_channel_attach_aio_context(client->ioc, client->exp->ctx);
+ }
+
assert(!client->optlen);
trace_nbd_negotiate_success();
--
1.8.3.1

91
kvm-virtio-blk-schedule-virtio_notify_config-to-run-on-m.patch Normal file
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@ -0,0 +1,91 @@
From 6b292920dbdd463bb80b82bef2063623a8e2da17 Mon Sep 17 00:00:00 2001
From: Sergio Lopez Pascual <slp@redhat.com>
Date: Fri, 27 Sep 2019 11:46:41 +0100
Subject: [PATCH 2/2] virtio-blk: schedule virtio_notify_config to run on main
context
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Sergio Lopez Pascual <slp@redhat.com>
Message-id: <20190927114641.20992-2-slp@redhat.com>
Patchwork-id: 90907
O-Subject: [RHEL-AV-8.1.0 qemu-kvm PATCH 1/1] virtio-blk: schedule virtio_notify_config to run on main context
Bugzilla: 1744955
RH-Acked-by: Eric Blake <eblake@redhat.com>
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
virtio_notify_config() needs to acquire the global mutex, which isn't
allowed from an iothread, and may lead to a deadlock like this:
- main thead
* Has acquired: qemu_global_mutex.
* Is trying the acquire: iothread AioContext lock via
AIO_WAIT_WHILE (after aio_poll).
- iothread
* Has acquired: AioContext lock.
* Is trying to acquire: qemu_global_mutex (via
virtio_notify_config->prepare_mmio_access).
If virtio_blk_resize() is called from an iothread, schedule
virtio_notify_config() to be run in the main context BH.
[Removed unnecessary newline as suggested by Kevin Wolf
<kwolf@redhat.com>.
--Stefan]
Signed-off-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 20190916112411.21636-1-slp@redhat.com
Message-Id: <20190916112411.21636-1-slp@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit f9a7e3698a737ee75a7b0af34203303df982550f)
Signed-off-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
hw/block/virtio-blk.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index cbb3729..0d9adcd 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -16,6 +16,7 @@
#include "qemu/iov.h"
#include "qemu/module.h"
#include "qemu/error-report.h"
+#include "qemu/main-loop.h"
#include "trace.h"
#include "hw/block/block.h"
#include "sysemu/blockdev.h"
@@ -1082,11 +1083,24 @@ static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f,
return 0;
}
+static void virtio_resize_cb(void *opaque)
+{
+ VirtIODevice *vdev = opaque;
+
+ assert(qemu_get_current_aio_context() == qemu_get_aio_context());
+ virtio_notify_config(vdev);
+}
+
static void virtio_blk_resize(void *opaque)
{
VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
- virtio_notify_config(vdev);
+ /*
+ * virtio_notify_config() needs to acquire the global mutex,
+ * so it can't be called from an iothread. Instead, schedule
+ * it to be run in the main context BH.
+ */
+ aio_bh_schedule_oneshot(qemu_get_aio_context(), virtio_resize_cb, vdev);
}
static const BlockDevOps virtio_block_ops = {
--
1.8.3.1

14
qemu-kvm.spec
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@ -67,7 +67,7 @@ Obsoletes: %1-rhev
Summary: QEMU is a machine emulator and virtualizer
Name: qemu-kvm
Version: 4.1.0
Release: 12%{?dist}
Release: 13%{?dist}
# Epoch because we pushed a qemu-1.0 package. AIUI this can't ever be dropped
Epoch: 15
License: GPLv2 and GPLv2+ and CC-BY
@ -216,6 +216,10 @@ Patch65: kvm-block-qcow2-Fix-corruption-introduced-by-commit-8ac0.patch
Patch66: kvm-block-qcow2-refactor-encryption-code.patch
# For bz#1745922 - Luks-inside-qcow2 snapshot cannot boot after 'qemu-img rebase'
Patch67: kvm-qemu-iotests-Add-test-for-bz-1745922.patch
# For bz#1748253 - QEMU crashes (core dump) when using the integrated NDB server with data-plane
Patch68: kvm-nbd-server-attach-client-channel-to-the-export-s-Aio.patch
# For bz#1744955 - Qemu hang when block resize a qcow2 image
Patch69: kvm-virtio-blk-schedule-virtio_notify_config-to-run-on-m.patch
BuildRequires: wget
BuildRequires: rpm-build
@ -1157,6 +1161,14 @@ useradd -r -u 107 -g qemu -G kvm -d / -s /sbin/nologin \
%changelog
* Fri Sep 27 2019 Danilo Cesar Lemes de Paula <ddepaula@redhat.com> - 4.1.0-13.el8
- kvm-nbd-server-attach-client-channel-to-the-export-s-Aio.patch [bz#1748253]
- kvm-virtio-blk-schedule-virtio_notify_config-to-run-on-m.patch [bz#1744955]
- Resolves: bz#1744955
(Qemu hang when block resize a qcow2 image)
- Resolves: bz#1748253
(QEMU crashes (core dump) when using the integrated NDB server with data-plane)
* Thu Sep 26 2019 Danilo Cesar Lemes de Paula <ddepaula@redhat.com> - 4.1.0-12.el8
- kvm-block-Use-QEMU_IS_ALIGNED.patch [bz#1745922]
- kvm-block-qcow2-Fix-corruption-introduced-by-commit-8ac0.patch [bz#1745922]