Re: [PATCH 2/2] qemu: Use virEventThreadStop() in qemuProcessStop()

On Thu, Jul 25, 2024 at 15:04:51 +0200, Michal Prívozník wrote: > On 7/25/24 14:33, Peter Krempa wrote: > > On Thu, Jul 25, 2024 at 12:57:59 +0200, Michal Privoznik wrote: > >> Currently, qemuProcessStop() unlocks given domain object right in > >> the middle of cleanup process. This is dangerous because there > >> might be another thread which is executing virDomainObjListAdd(). > >> And since the domain object is on the list of domain objects AND > >> by the time qemuProcessStop() unlocks it the object is also > >> marked as inactive, the other thread acquires the lock and > >> switches vm->def pointer. > >> > >> The unlocking of domain object is needed though, to allow even > >> processing thread finish its queue. Well, the processing can be > >> done before any cleanup is attempted. > >> > >> Therefore, use freshly introduced virEventThreadStop() to join > >> the event thread and drop lock/unlock from the middle of > >> qemuProcessStop(). > >> > >> Fixes: 3865410e7f67ca4ec66e9a905e75f452762a97f0 > >> Resolves: https://issues.redhat.com/browse/RHEL-49607 > >> Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > >> --- > >> src/qemu/qemu_process.c | 14 ++++++++++---- > >> 1 file changed, 10 insertions(+), 4 deletions(-) > >> > >> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c > >> index 6255ba92e7..0869307a90 100644 > >> --- a/src/qemu/qemu_process.c > >> +++ b/src/qemu/qemu_process.c > >> @@ -8615,6 +8615,14 @@ void qemuProcessStop(virQEMUDriver *driver, So we're still in qemuProcessStop ... > >> * reporting so we don't squash a legit error. */ > >> virErrorPreserveLast(&orig_err); > >> > >> + /* By unlocking the domain object the events processing thread is > >> + * allowed to finish its job. */