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@redhat.com>
Introduce use of a virDomainDefPtr in the domain coredump
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain stats &
peek APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain scheduler
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain autostart
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain hotplug
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain VCPU
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain create, migrate,
getxml, & define APIs to simplify introduction of ACL security
checks. The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain save
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain property
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain lifecycle
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Introduce use of a virDomainDefPtr in the domain lookup
APIs to simplify introduction of ACL security checks.
The virDomainPtr cannot be safely used, since the app
may have supplied mis-matching name/uuid/id fields. eg
the name points to domain X, while the uuid points to
domain Y. Resolving the virDomainPtr to a virDomainDefPtr
ensures a consistent name/uuid/id set.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The shunloadStart function didn't check the status of virInitialize which
was flagged by Coverity. Adjust the function and shunloadtest in order
to handle the situation.
In 84c59ffa I've tried to fix changing ejectable media process. The
process should go like this:
1) we need to call 'eject' on the monitor
2) we should wait for 'DEVICE_TRAY_MOVED' event
3) now we can issue 'change' command
However, while waiting in step 2) the domain monitor was locked. So
even if qemu reported the desired event, the proper callback was not
called immediately. The monitor handling code needs to lock the
monitor in order to read the event. So that's the first lock we must
not hold while waiting. The second one is the domain lock. When
monitor handling code reads an event, the appropriate callback is
called then. The first thing that each callback does is locking the
corresponding domain as a domain or its device is about to change
state. So we need to unlock both monitor and VM lock. Well, holding
any lock while sleep()-ing is not the best thing to do anyway.
To ensure we don't regress and cause the need for further
cleanups, add a 'make syntax-check' rule that ensures new
files have proper copyright contents.
* cfg.mk (sc_copyright_address): Rename...
(sc_copyright_usage): ...and enhance.
Signed-off-by: Eric Blake <eblake@redhat.com>
