Re: [PATCH 1/5] hw/char/dw8250: Fix leak when creating child device

[Daniel Henrique Barboza]

Hi Portia,

I believe this fix should be made by the original patch that introduces the 
device,
which isn't upstreamed yet:

[PATCH v5 1/7] hw/char: Add dw8250 UART
https://lore.kernel.org/qemu-devel/20260927201326.650943-2-visitor...@gmail.com/


Thanks,
Daniel

On 9/29/2026 12:16 AM, port...@oss.tenstorrent.com wrote:

From: Portia Stephens <port...@oss.tenstorrent.com>

dw8250_instance_init() creates two references for serial_mm, one from
qdev_new() and one from object_property_add_child() which leaks the
serial_mm object. Fix embedding the SerialMM struct in the DW8250State.

Signed-off-by: Portia Stephens <port...@oss.tenstorrent.com>
---
  hw/char/dw8250.c         | 11 +++++------
  include/hw/char/dw8250.h |  3 ++-
  2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/hw/char/dw8250.c b/hw/char/dw8250.c
index ccf05dd9ad..50baeae62c 100644
--- a/hw/char/dw8250.c
+++ b/hw/char/dw8250.c
@@ -72,23 +72,22 @@ static void dw8250_instance_init(Object *obj)
  {
      DW8250State *s = DW8250(obj);

- s->serial_mm = qdev_new("serial-mm");

-    object_property_add_child(obj, "serial-mm", OBJECT(s->serial_mm));
-    object_property_add_alias(obj, "chardev", OBJECT(s->serial_mm), "chardev");
+    object_initialize_child(obj, "serial-mm", &s->serial_mm, TYPE_SERIAL_MM);
+    object_property_add_alias(obj, "chardev", OBJECT(&s->serial_mm), 
"chardev");
  }

static void dw8250_realize(DeviceState *dev, Error **errp)

  {
      DW8250State *s = DW8250(dev);
      SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
-    SysBusDevice *serial_sbd = SYS_BUS_DEVICE(s->serial_mm);
+    SysBusDevice *serial_sbd = SYS_BUS_DEVICE(&s->serial_mm);

memory_region_init(&s->container, OBJECT(dev), "dw8250-container",

                         DW_UART_REGION_SIZE);
      sysbus_init_mmio(sbd, &s->container);

- qdev_prop_set_uint8(s->serial_mm, "regshift", s->regshift);

-    qdev_prop_set_uint8(s->serial_mm, "endianness", DEVICE_LITTLE_ENDIAN);
+    qdev_prop_set_uint8(DEVICE(&s->serial_mm), "regshift", s->regshift);
+    qdev_prop_set_uint8(DEVICE(&s->serial_mm), "endianness", 
DEVICE_LITTLE_ENDIAN);
      if (!sysbus_realize(serial_sbd, errp)) {
          return;
      }
diff --git a/include/hw/char/dw8250.h b/include/hw/char/dw8250.h
index 59396ad202..ce0b97715b 100644
--- a/include/hw/char/dw8250.h
+++ b/include/hw/char/dw8250.h
@@ -10,6 +10,7 @@

#include "hw/core/sysbus.h"

  #include "qom/object.h"
+#include "hw/char/serial-mm.h"

#define TYPE_DW8250 "dw8250"

  OBJECT_DECLARE_SIMPLE_TYPE(DW8250State, DW8250)
@@ -19,7 +20,7 @@ struct DW8250State {

MemoryRegion container;

      MemoryRegion ext_iomem;
-    DeviceState *serial_mm;
+    SerialMM serial_mm;

uint8_t regshift;

  };