* [Qemu-devel] [PATCH 2/4] object: fix OBJ_PROP_LINK_UNREF_ON_RELEASE ambivalence
2018-05-31 19:51 [Qemu-devel] [PATCH 0/4] Fix usb-ccid hotplug regression Marc-André Lureau
2018-05-31 19:51 ` [Qemu-devel] [PATCH 1/4] bus: do not unref the added child bus on realize Marc-André Lureau
@ 2018-05-31 19:51 ` Marc-André Lureau
2018-05-31 19:51 ` [Qemu-devel] [PATCH 3/4] usb-ccid: fix bus leak Marc-André Lureau
` (2 subsequent siblings)
4 siblings, 0 replies; 7+ messages in thread
From: Marc-André Lureau @ 2018-05-31 19:51 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, spopovyc, kraxel, Marc-André Lureau
A link property can be set during creation, with
object_property_add_link() and later with object_property_set_link().
add_link() doesn't add a reference to the target object, while
set_link() does.
Furthemore, OBJ_PROP_LINK_UNREF_ON_RELEASE flags, set during add_link,
says whether a reference must be released when the property is destroyed.
This can lead to leaks if the property was later set_link(), as the
added reference is never released.
Instead, rename OBJ_PROP_LINK_UNREF_ON_RELEASE to OBJ_PROP_LINK_STRONG
and use that has an indication on how the link handle reference
management in set_link().
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
include/qom/object.h | 12 +++++++++---
hw/core/qdev-properties.c | 2 +-
hw/core/qdev.c | 2 +-
hw/display/xlnx_dp.c | 2 +-
hw/dma/xilinx_axidma.c | 4 ++--
hw/dma/xlnx-zdma.c | 2 +-
hw/i386/pc.c | 2 +-
hw/i386/pc_piix.c | 2 +-
hw/i386/pc_q35.c | 2 +-
hw/ipmi/ipmi.c | 2 +-
hw/net/xilinx_axienet.c | 4 ++--
hw/ssi/xilinx_spips.c | 2 +-
net/can/can_host.c | 2 +-
net/colo-compare.c | 2 +-
qom/object.c | 8 +++++---
target/arm/cpu.c | 4 ++--
ui/console.c | 2 +-
17 files changed, 32 insertions(+), 24 deletions(-)
diff --git a/include/qom/object.h b/include/qom/object.h
index a0c78c76f7..f3d2308d56 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1103,6 +1103,11 @@ char *object_property_get_str(Object *obj, const char *name,
* @errp: returns an error if this function fails
*
* Writes an object's canonical path to a property.
+ *
+ * If the link property was created with
+ * <code>OBJ_PROP_LINK_STRONG</code> bit, the old target object is
+ * unreferenced, and a reference is added to the new target object.
+ *
*/
void object_property_set_link(Object *obj, Object *value,
const char *name, Error **errp);
@@ -1394,7 +1399,7 @@ void object_property_add_child(Object *obj, const char *name,
typedef enum {
/* Unref the link pointer when the property is deleted */
- OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1,
+ OBJ_PROP_LINK_STRONG = 0x1,
} ObjectPropertyLinkFlags;
/**
@@ -1432,8 +1437,9 @@ void object_property_allow_set_link(const Object *, const char *,
* link property. The reference count for <code>*@child</code> is
* managed by the property from after the function returns till the
* property is deleted with object_property_del(). If the
- * <code>@flags</code> <code>OBJ_PROP_LINK_UNREF_ON_RELEASE</code> bit is set,
- * the reference count is decremented when the property is deleted.
+ * <code>@flags</code> <code>OBJ_PROP_LINK_STRONG</code> bit is set,
+ * the reference count is decremented when the property is deleted or
+ * modified.
*/
void object_property_add_link(Object *obj, const char *name,
const char *type, Object **child,
diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
index 5bbc2d98b5..f3a83a3643 100644
--- a/hw/core/qdev-properties.c
+++ b/hw/core/qdev-properties.c
@@ -1309,7 +1309,7 @@ static void create_link_property(Object *obj, Property *prop, Error **errp)
object_property_add_link(obj, prop->name, prop->link_type,
child,
qdev_prop_allow_set_link_before_realize,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
errp);
}
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index f6f92473b8..ce7c316552 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -435,7 +435,7 @@ void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq *pins,
object_property_add_link(OBJECT(dev), propname, TYPE_IRQ,
(Object **)&pins[i],
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
g_free(propname);
}
diff --git a/hw/display/xlnx_dp.c b/hw/display/xlnx_dp.c
index 6715b9cc2b..b737e1d3af 100644
--- a/hw/display/xlnx_dp.c
+++ b/hw/display/xlnx_dp.c
@@ -1221,7 +1221,7 @@ static void xlnx_dp_init(Object *obj)
object_property_add_link(obj, "dpdma", TYPE_XLNX_DPDMA,
(Object **) &s->dpdma,
xlnx_dp_set_dpdma,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
/*
diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
index 9b48103574..401a328e27 100644
--- a/hw/dma/xilinx_axidma.c
+++ b/hw/dma/xilinx_axidma.c
@@ -525,12 +525,12 @@ static void xilinx_axidma_realize(DeviceState *dev, Error **errp)
object_property_add_link(OBJECT(ds), "dma", TYPE_XILINX_AXI_DMA,
(Object **)&ds->dma,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&local_err);
object_property_add_link(OBJECT(cs), "dma", TYPE_XILINX_AXI_DMA,
(Object **)&cs->dma,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&local_err);
if (local_err) {
goto xilinx_axidma_realize_fail;
diff --git a/hw/dma/xlnx-zdma.c b/hw/dma/xlnx-zdma.c
index 8eea757aff..b6745f5bcf 100644
--- a/hw/dma/xlnx-zdma.c
+++ b/hw/dma/xlnx-zdma.c
@@ -787,7 +787,7 @@ static void zdma_init(Object *obj)
object_property_add_link(obj, "dma", TYPE_MEMORY_REGION,
(Object **)&s->dma_mr,
qdev_prop_allow_set_link_before_realize,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
}
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index d768930d02..1aaa60a5d4 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -484,7 +484,7 @@ void pc_cmos_init(PCMachineState *pcms,
TYPE_ISA_DEVICE,
(Object **)&pcms->rtc,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
+ OBJ_PROP_LINK_STRONG, &error_abort);
object_property_set_link(OBJECT(pcms), OBJECT(s),
"rtc_state", &error_abort);
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index b4c5b03274..3b87f3cedb 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -289,7 +289,7 @@ static void pc_init1(MachineState *machine,
TYPE_HOTPLUG_HANDLER,
(Object **)&pcms->acpi_dev,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
+ OBJ_PROP_LINK_STRONG, &error_abort);
object_property_set_link(OBJECT(machine), OBJECT(piix4_pm),
PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
}
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 83d6d75efa..087f2630f9 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -194,7 +194,7 @@ static void pc_q35_init(MachineState *machine)
TYPE_HOTPLUG_HANDLER,
(Object **)&pcms->acpi_dev,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE, &error_abort);
+ OBJ_PROP_LINK_STRONG, &error_abort);
object_property_set_link(OBJECT(machine), OBJECT(lpc),
PC_MACHINE_ACPI_DEVICE_PROP, &error_abort);
diff --git a/hw/ipmi/ipmi.c b/hw/ipmi/ipmi.c
index 9be281fd87..63c031703d 100644
--- a/hw/ipmi/ipmi.c
+++ b/hw/ipmi/ipmi.c
@@ -104,7 +104,7 @@ void ipmi_bmc_find_and_link(Object *obj, Object **bmc)
{
object_property_add_link(obj, "bmc", TYPE_IPMI_BMC, bmc,
isa_ipmi_bmc_check,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
}
diff --git a/hw/net/xilinx_axienet.c b/hw/net/xilinx_axienet.c
index d4c2c89dc1..cc880a3d08 100644
--- a/hw/net/xilinx_axienet.c
+++ b/hw/net/xilinx_axienet.c
@@ -951,12 +951,12 @@ static void xilinx_enet_realize(DeviceState *dev, Error **errp)
object_property_add_link(OBJECT(ds), "enet", "xlnx.axi-ethernet",
(Object **) &ds->enet,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&local_err);
object_property_add_link(OBJECT(cs), "enet", "xlnx.axi-ethernet",
(Object **) &cs->enet,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&local_err);
if (local_err) {
goto xilinx_enet_realize_fail;
diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
index 03f5faee4b..f599025956 100644
--- a/hw/ssi/xilinx_spips.c
+++ b/hw/ssi/xilinx_spips.c
@@ -1346,7 +1346,7 @@ static void xlnx_zynqmp_qspips_init(Object *obj)
object_property_add_link(obj, "stream-connected-dma", TYPE_STREAM_SLAVE,
(Object **)&rq->dma,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
NULL);
}
diff --git a/net/can/can_host.c b/net/can/can_host.c
index c3d26521cd..c79347abab 100644
--- a/net/can/can_host.c
+++ b/net/can/can_host.c
@@ -77,7 +77,7 @@ static void can_host_instance_init(Object *obj)
object_property_add_link(obj, "canbus", TYPE_CAN_BUS,
(Object **)&ch->bus,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
}
diff --git a/net/colo-compare.c b/net/colo-compare.c
index 23b2d2c4cc..63469b11a1 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -980,7 +980,7 @@ static void colo_compare_init(Object *obj)
object_property_add_link(obj, "iothread", TYPE_IOTHREAD,
(Object **)&s->iothread,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
+ OBJ_PROP_LINK_STRONG, NULL);
s->vnet_hdr = false;
object_property_add_bool(obj, "vnet_hdr_support", compare_get_vnet_hdr,
diff --git a/qom/object.c b/qom/object.c
index 0fc972030e..bfec376628 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1564,9 +1564,11 @@ static void object_set_link_property(Object *obj, Visitor *v,
return;
}
- object_ref(new_target);
*child = new_target;
- object_unref(old_target);
+ if (prop->flags == OBJ_PROP_LINK_STRONG) {
+ object_ref(new_target);
+ object_unref(old_target);
+ }
}
static Object *object_resolve_link_property(Object *parent, void *opaque, const gchar *part)
@@ -1581,7 +1583,7 @@ static void object_release_link_property(Object *obj, const char *name,
{
LinkProperty *prop = opaque;
- if ((prop->flags & OBJ_PROP_LINK_UNREF_ON_RELEASE) && *prop->child) {
+ if ((prop->flags & OBJ_PROP_LINK_STRONG) && *prop->child) {
object_unref(*prop->child);
}
g_free(prop);
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 5d60893a07..ab047b9402 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -690,7 +690,7 @@ static void arm_cpu_post_init(Object *obj)
TYPE_MEMORY_REGION,
(Object **)&cpu->secure_memory,
qdev_prop_allow_set_link_before_realize,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
#endif
}
@@ -718,7 +718,7 @@ static void arm_cpu_post_init(Object *obj)
if (arm_feature(&cpu->env, ARM_FEATURE_M_SECURITY)) {
object_property_add_link(obj, "idau", TYPE_IDAU_INTERFACE, &cpu->idau,
qdev_prop_allow_set_link_before_realize,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
qdev_property_add_static(DEVICE(obj), &arm_cpu_initsvtor_property,
&error_abort);
diff --git a/ui/console.c b/ui/console.c
index ef1247f872..bc58458ee8 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1287,7 +1287,7 @@ static QemuConsole *new_console(DisplayState *ds, console_type_t console_type,
object_property_add_link(obj, "device", TYPE_DEVICE,
(Object **)&s->device,
object_property_allow_set_link,
- OBJ_PROP_LINK_UNREF_ON_RELEASE,
+ OBJ_PROP_LINK_STRONG,
&error_abort);
object_property_add_uint32_ptr(obj, "head",
&s->head, &error_abort);
--
2.17.1.906.g10fd178552
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