[gentoo-commits] gentoo-x86 commit in app-emulation/libvirt/files: libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch

[Doug Goldstein (cardoe)]

cardoe      13/05/28 17:07:00

  Added:               
                        libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch
                        libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch
  Log:
  Bump to fix cgroup movement race and nbd based migrations on IPv6 enabled hosts.
  
  (Portage version: 2.1.11.62/cvs/Linux x86_64, signed Manifest commit with key D7DFA8D318FA9AEF!)

Revision  Changes    Path
1.1                  app-emulation/libvirt/files/libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch

file : http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-emulation/libvirt/files/libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch?rev=1.1&view=markup
plain: http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-emulation/libvirt/files/libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch?rev=1.1&content-type=text/plain

Index: libvirt-1.0.5.1-0001-cgroup-be-robust-against-cgroup-movement-races.patch
===================================================================
From b4541a2f3d7ed9e1522065195b4f31529228e493 Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@××××××.com>
Date: Mon, 20 May 2013 20:30:30 -0600
Subject: [PATCH 1/2] cgroup: be robust against cgroup movement races

https://bugzilla.redhat.com/show_bug.cgi?id=965169 documents a
problem starting domains when cgroups are enabled; I was able
to reliably reproduce the race about 5% of the time when I added
hooks to domain startup by 3 seconds (as that seemed to be about
the length of time that qemu created and then closed a temporary
thread, probably related to aio handling of initially opening
a disk image).  The problem has existed since we introduced
virCgroupMoveTask in commit 9102829 (v0.10.0).

There are some inherent TOCTTOU races when moving tasks between
kernel cgroups, precisely because threads can be created or
completed in the window between when we read a thread id from the
source and when we write to the destination.  As the goal of
virCgroupMoveTask is merely to move ALL tasks into the new
cgroup, it is sufficient to iterate until no more threads are
being created in the old group, and ignoring any threads that
die before we can move them.

It would be nicer to start the threads in the right cgroup to
begin with, but by default, all child threads are created in
the same cgroup as their parent, and we don't want vcpu child
threads in the emulator cgroup, so I don't see any good way
of avoiding the move.  It would also be nice if the kernel were
to implement something like rename() as a way to atomically move
a group of threads from one cgroup to another, instead of forcing
a window where we have to read and parse the source, then format
and write back into the destination.

* src/util/vircgroup.c (virCgroupAddTaskStrController): Ignore
ESRCH, because a thread ended between read and write attempts.
(virCgroupMoveTask): Loop until all threads have moved.

Signed-off-by: Eric Blake <eblake@××××××.com>
(cherry picked from commit 83e4c77547f5b721afad19a452f41c31daeee8c5)
---
 src/util/vircgroup.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index b05fc45..92b185e 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -1037,7 +1037,11 @@ static int virCgroupAddTaskStrController(virCgroupPtr group,
             goto cleanup;
 
         rc = virCgroupAddTaskController(group, p, controller);
-        if (rc != 0)
+        /* A thread that exits between when we first read the source
+         * tasks and now is not fatal.  */
+        if (rc == -ESRCH)
+            rc = 0;
+        else if (rc != 0)
             goto cleanup;
 
         next = strchr(cur, '\n');
@@ -1074,15 +1078,23 @@ int virCgroupMoveTask(virCgroupPtr src_group, virCgroupPtr dest_group)
             !dest_group->controllers[i].mountPoint)
             continue;
 
-        rc = virCgroupGetValueStr(src_group, i, "tasks", &content);
-        if (rc != 0)
-            return rc;
+        /* New threads are created in the same group as their parent;
+         * but if a thread is created after we first read we aren't
+         * aware that it needs to move.  Therefore, we must iterate
+         * until content is empty.  */
+        while (1) {
+            rc = virCgroupGetValueStr(src_group, i, "tasks", &content);
+            if (rc != 0)
+                return rc;
+            if (!*content)
+                break;
 
-        rc = virCgroupAddTaskStrController(dest_group, content, i);
-        if (rc != 0)
-            goto cleanup;
+            rc = virCgroupAddTaskStrController(dest_group, content, i);
+            if (rc != 0)
+                goto cleanup;
 
-        VIR_FREE(content);
+            VIR_FREE(content);
+        }
     }
 
 cleanup:
-- 
1.8.1.5




1.1                  app-emulation/libvirt/files/libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch

file : http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-emulation/libvirt/files/libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch?rev=1.1&view=markup
plain: http://sources.gentoo.org/viewvc.cgi/gentoo-x86/app-emulation/libvirt/files/libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch?rev=1.1&content-type=text/plain

Index: libvirt-1.0.5.1-0002-qemu-fix-NBD-migration-to-hosts-with-IPv6-enabled.patch
===================================================================
From 3accd7eb25f3646e15511af4cb0d09c3bf2ce143 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A1n=20Tomko?= <jtomko@××××××.com>
Date: Thu, 23 May 2013 15:51:05 +0200
Subject: [PATCH 2/2] qemu: fix NBD migration to hosts with IPv6 enabled

Since f03dcc5 we use [::] as the listening address both on qemu
command line in -incoming and in nbd-server-start QMP command.
However the latter requires just :: without the braces.
(cherry picked from commit 2326006410a921bba38c0ce67a367cd1ea88cc33)
---
 src/qemu/qemu_migration.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 6ad1c30..adc967a 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1114,6 +1114,12 @@ qemuMigrationStartNBDServer(virQEMUDriverPtr driver,
     unsigned short port = 0;
     char *diskAlias = NULL;
     size_t i;
+    const char *host;
+
+    if (STREQ(listenAddr, "[::]"))
+        host = "::";
+    else
+        host = listenAddr;
 
     for (i = 0; i < vm->def->ndisks; i++) {
         virDomainDiskDefPtr disk = vm->def->disks[i];
@@ -1135,7 +1141,7 @@ qemuMigrationStartNBDServer(virQEMUDriverPtr driver,
 
         if (!port &&
             ((virPortAllocatorAcquire(driver->remotePorts, &port) < 0) ||
-             (qemuMonitorNBDServerStart(priv->mon, listenAddr, port) < 0))) {
+             (qemuMonitorNBDServerStart(priv->mon, host, port) < 0))) {
             qemuDomainObjExitMonitor(driver, vm);
             goto cleanup;
         }
-- 
1.8.1.5