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

[Pan Nengyuan]

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.

> 
> 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>
> 
> .
>