On Thu, 7 May 2020 11:38:04 +0000 "Zhang, Chen" wrote: > > -----Original Message----- > > From: Lukas Straub > > Sent: Monday, May 4, 2020 6:28 PM > > To: qemu-devel > > Cc: Zhang, Chen ; Li Zhijian > > ; Jason Wang ; Marc- > > André Lureau ; Paolo Bonzini > > > > Subject: [PATCH v4 5/6] net/colo-compare.c, softmmu/vl.c: Check that colo- > > compare is active > > > > If the colo-compare object is removed before failover and a checkpoint > > happens, qemu crashes because it tries to lock the destroyed event_mtx in > > colo_notify_compares_event. > > > > Fix this by checking if everything is initialized by introducing a new variable > > colo_compare_active which is protected by a new mutex > > colo_compare_mutex. The new mutex also protects against concurrent > > access of the net_compares list and makes sure that > > colo_notify_compares_event isn't active while we destroy event_mtx and > > event_complete_cond. > > > > With this it also is again possible to use colo without colo-compare (periodic > > mode) and to use multiple colo-compare for multiple network interfaces. > > > > Hi Lukas, > > For this case I think we don't need to touch vl.c code, we can solve this issue from another perspective: > How to remove colo-compare? > User will use qemu-monitor or QMP command to disable an object, so we just need return operation failed > When user try to remove colo-compare object while COLO is running. Yeah, but that still leaves the other problem that colo can't be used without colo-compare (qemu crashes then). Regards, Lukas Straub > Thanks > Zhang Chen > > > Signed-off-by: Lukas Straub > > --- > > net/colo-compare.c | 35 +++++++++++++++++++++++++++++------ > > net/colo-compare.h | 1 + > > softmmu/vl.c | 2 ++ > > 3 files changed, 32 insertions(+), 6 deletions(-) > > > > diff --git a/net/colo-compare.c b/net/colo-compare.c index > > 56db3d3bfc..c7572d75e9 100644 > > --- a/net/colo-compare.c > > +++ b/net/colo-compare.c > > @@ -54,6 +54,8 @@ static NotifierList colo_compare_notifiers = #define > > REGULAR_PACKET_CHECK_MS 3000 #define DEFAULT_TIME_OUT_MS 3000 > > > > +static QemuMutex colo_compare_mutex; > > +static bool colo_compare_active; > > static QemuMutex event_mtx; > > static QemuCond event_complete_cond; > > static int event_unhandled_count; > > @@ -906,6 +908,12 @@ static void check_old_packet_regular(void *opaque) > > void colo_notify_compares_event(void *opaque, int event, Error **errp) { > > CompareState *s; > > + qemu_mutex_lock(&colo_compare_mutex); > > + > > + if (!colo_compare_active) { > > + qemu_mutex_unlock(&colo_compare_mutex); > > + return; > > + } > > > > qemu_mutex_lock(&event_mtx); > > QTAILQ_FOREACH(s, &net_compares, next) { @@ -919,6 +927,7 @@ void > > colo_notify_compares_event(void *opaque, int event, Error **errp) > > } > > > > qemu_mutex_unlock(&event_mtx); > > + qemu_mutex_unlock(&colo_compare_mutex); > > } > > > > static void colo_compare_timer_init(CompareState *s) @@ -1274,7 +1283,14 > > @@ static void colo_compare_complete(UserCreatable *uc, Error **errp) > > s->vnet_hdr); > > } > > > > + qemu_mutex_lock(&colo_compare_mutex); > > + if (!colo_compare_active) { > > + qemu_mutex_init(&event_mtx); > > + qemu_cond_init(&event_complete_cond); > > + colo_compare_active = true; > > + } > > QTAILQ_INSERT_TAIL(&net_compares, s, next); > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > s->out_sendco.s = s; > > s->out_sendco.chr = &s->chr_out; > > @@ -1290,9 +1306,6 @@ static void colo_compare_complete(UserCreatable > > *uc, Error **errp) > > > > g_queue_init(&s->conn_list); > > > > - qemu_mutex_init(&event_mtx); > > - qemu_cond_init(&event_complete_cond); > > - > > s->connection_track_table = > > g_hash_table_new_full(connection_key_hash, > > connection_key_equal, > > g_free, @@ -1384,12 +1397,19 @@ static void > > colo_compare_finalize(Object *obj) > > > > qemu_bh_delete(s->event_bh); > > > > + qemu_mutex_lock(&colo_compare_mutex); > > QTAILQ_FOREACH(tmp, &net_compares, next) { > > if (tmp == s) { > > QTAILQ_REMOVE(&net_compares, s, next); > > break; > > } > > } > > + if (QTAILQ_EMPTY(&net_compares)) { > > + colo_compare_active = false; > > + qemu_mutex_destroy(&event_mtx); > > + qemu_cond_destroy(&event_complete_cond); > > + } > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > AioContext *ctx = iothread_get_aio_context(s->iothread); > > aio_context_acquire(ctx); > > @@ -1413,15 +1433,18 @@ static void colo_compare_finalize(Object *obj) > > object_unref(OBJECT(s->iothread)); > > } > > > > - qemu_mutex_destroy(&event_mtx); > > - qemu_cond_destroy(&event_complete_cond); > > - > > g_free(s->pri_indev); > > g_free(s->sec_indev); > > g_free(s->outdev); > > g_free(s->notify_dev); > > } > > > > +void colo_compare_init_globals(void) > > +{ > > + colo_compare_active = false; > > + qemu_mutex_init(&colo_compare_mutex); > > +} > > + > > static const TypeInfo colo_compare_info = { > > .name = TYPE_COLO_COMPARE, > > .parent = TYPE_OBJECT, > > diff --git a/net/colo-compare.h b/net/colo-compare.h index > > 22ddd512e2..eb483ac586 100644 > > --- a/net/colo-compare.h > > +++ b/net/colo-compare.h > > @@ -17,6 +17,7 @@ > > #ifndef QEMU_COLO_COMPARE_H > > #define QEMU_COLO_COMPARE_H > > > > +void colo_compare_init_globals(void); > > void colo_notify_compares_event(void *opaque, int event, Error **errp); > > void colo_compare_register_notifier(Notifier *notify); void > > colo_compare_unregister_notifier(Notifier *notify); diff --git a/softmmu/vl.c > > b/softmmu/vl.c index 32c0047889..a913ed5469 100644 > > --- a/softmmu/vl.c > > +++ b/softmmu/vl.c > > @@ -112,6 +112,7 @@ > > #include "qapi/qmp/qerror.h" > > #include "sysemu/iothread.h" > > #include "qemu/guest-random.h" > > +#include "net/colo-compare.h" > > > > #define MAX_VIRTIO_CONSOLES 1 > > > > @@ -2906,6 +2907,7 @@ void qemu_init(int argc, char **argv, char **envp) > > precopy_infrastructure_init(); > > postcopy_infrastructure_init(); > > monitor_init_globals(); > > + colo_compare_init_globals(); > > > > if (qcrypto_init(&err) < 0) { > > error_reportf_err(err, "cannot initialize crypto: "); > > -- > > 2.20.1 >