Re: [PATCH v2] virtio-serial-bus: do cleanup on the error path in realize() to avoid memleaks

[Michael S. Tsirkin]

On Fri, Mar 06, 2020 at 05:35:06PM +0800, Pan Nengyuan wrote:
> 
> 
> On 3/6/2020 4:51 PM, Markus Armbruster wrote:
> > Pan Nengyuan <address@hidden> writes:
> > 
> >> port->bh forgot to delete on the error path, this patch add it to fix 
> >> memleaks. It's easy to reproduce as follow(add a same nr port):
> > 
> > Long line.  Suggest:
> > 
> >     virtio-serial-bus: Plug memory leak on realize() error paths
> > 
> >     We neglect to free port->bh on the error paths.  Fix that.
> >     Reproducer:
> Good suggestion. Looks simple and clear.
> 
> Thanks.


OK pls repost with acks and fixed commit log.

> > 
> > Perhaps the maintainer can tweak this for you without a respin.
> > 
> >>     {'execute': 'device_add', 'arguments': {'id': 'virtio_serial_pci0', 
> >> 'driver': 'virtio-serial-pci', 'bus': 'pci.0', 'addr': '0x5'}, 'id': 
> >> 'yVkZcGgV'}
> >>     {'execute': 'device_add', 'arguments': {'id': 'port1', 'driver': 
> >> 'virtserialport', 'name': 'port1', 'chardev': 'channel1', 'bus': 
> >> 'virtio_serial_pci0.0', 'nr': 1}, 'id': '3dXdUgJA'}
> >>     {'execute': 'device_add', 'arguments': {'id': 'port2', 'driver': 
> >> 'virtserialport', 'name': 'port2', 'chardev': 'channel2', 'bus': 
> >> 'virtio_serial_pci0.0', 'nr': 1}, 'id': 'qLzcCkob'}
> >>     {'execute': 'device_add', 'arguments': {'id': 'port2', 'driver': 
> >> 'virtserialport', 'name': 'port2', 'chardev': 'channel2', 'bus': 
> >> 'virtio_serial_pci0.0', 'nr': 2}, 'id': 'qLzcCkob'}
> >>
> >> The leak stack:
> >> Direct leak of 40 byte(s) in 1 object(s) allocated from:
> >>     #0 0x7f04a8008ae8 in __interceptor_malloc (/lib64/libasan.so.5+0xefae8)
> >>     #1 0x7f04a73cf1d5 in g_malloc (/lib64/libglib-2.0.so.0+0x531d5)
> >>     #2 0x56273eaee484 in aio_bh_new /mnt/sdb/backup/qemu/util/async.c:125
> >>     #3 0x56273eafe9a8 in qemu_bh_new 
> >> /mnt/sdb/backup/qemu/util/main-loop.c:532
> >>     #4 0x56273d52e62e in virtser_port_device_realize 
> >> /mnt/sdb/backup/qemu/hw/char/virtio-serial-bus.c:946
> >>     #5 0x56273dcc5040 in device_set_realized 
> >> /mnt/sdb/backup/qemu/hw/core/qdev.c:891
> >>     #6 0x56273e5ebbce in property_set_bool 
> >> /mnt/sdb/backup/qemu/qom/object.c:2238
> >>     #7 0x56273e5e5a9c in object_property_set 
> >> /mnt/sdb/backup/qemu/qom/object.c:1324
> >>     #8 0x56273e5ef5f8 in object_property_set_qobject 
> >> /mnt/sdb/backup/qemu/qom/qom-qobject.c:26
> >>     #9 0x56273e5e5e6a in object_property_set_bool 
> >> /mnt/sdb/backup/qemu/qom/object.c:1390
> >>     #10 0x56273daa40de in qdev_device_add 
> >> /mnt/sdb/backup/qemu/qdev-monitor.c:680
> >>     #11 0x56273daa53e9 in qmp_device_add 
> >> /mnt/sdb/backup/qemu/qdev-monitor.c:805
> >>
> >> Fixes: 199646d81522509ac2dba6d28c31e8c7d807bc93
> >> Reported-by: Euler Robot <address@hidden>
> >> Signed-off-by: Pan Nengyuan <address@hidden>
> >> ---
> >> v1->v2:
> >> - simply create port->bh last in virtser_port_device_realize() to fix 
> >> memleaks.(Suggested by Markus Armbruster)
> >> ---
> >>  hw/char/virtio-serial-bus.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> >> index 941ed5aca9..99a65bab7f 100644
> >> --- a/hw/char/virtio-serial-bus.c
> >> +++ b/hw/char/virtio-serial-bus.c
> >> @@ -943,7 +943,6 @@ static void virtser_port_device_realize(DeviceState 
> >> *dev, Error **errp)
> >>      Error *err = NULL;
> >>  
> >>      port->vser = bus->vser;
> >> -    port->bh = qemu_bh_new(flush_queued_data_bh, port);
> >>  
> >>      assert(vsc->have_data);
> >>  
> >> @@ -992,6 +991,7 @@ static void virtser_port_device_realize(DeviceState 
> >> *dev, Error **errp)
> >>          return;
> >>      }
> >>  
> >> +    port->bh = qemu_bh_new(flush_queued_data_bh, port);
> >>      port->elem = NULL;
> >>  }
> > 
> > Preferably with a tidied up commit message:
> > Reviewed-by: Markus Armbruster <address@hidden>
> > 
> > .
> >