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Re: [Qemu-devel] [PATCH 2/6] qdev: unref qdev when device_add fails
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 2/6] qdev: unref qdev when device_add fails |
Date: |
Tue, 10 Sep 2013 18:49:31 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 |
Il 10/09/2013 18:21, Stefan Hajnoczi ha scritto:
> qdev_device_add() leaks the created qdev upon failure. I suspect this
> problem crept in because qdev_free() unparents the qdev but does not
> drop a reference - confusing name.
Right, the name a leftover from pre-refcounting days.
BTW, not dropping a reference is the right thing to do because the
reference is dropped much earlier, typically as soon as qdev_device_add
returns. The QOM object tree then will still provide means to access
devices, until they are unparented.
In this case, however, qdev_device_add's caller does not have a
reference to free; doing that is the responsibility of qdev_device_add,
since it returns NULL.
> Also drop trailing whitespace after curly bracket.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> qdev-monitor.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/qdev-monitor.c b/qdev-monitor.c
> index 410cdcb..5657cdc 100644
> --- a/qdev-monitor.c
> +++ b/qdev-monitor.c
> @@ -512,6 +512,7 @@ DeviceState *qdev_device_add(QemuOpts *opts)
> }
> if (qemu_opt_foreach(opts, set_property, qdev, 1) != 0) {
> qdev_free(qdev);
> + object_unref(OBJECT(qdev));
> return NULL;
> }
> if (qdev->id) {
> @@ -523,8 +524,9 @@ DeviceState *qdev_device_add(QemuOpts *opts)
> object_property_add_child(qdev_get_peripheral_anon(), name,
> OBJECT(qdev), NULL);
> g_free(name);
> - }
> + }
> if (qdev_init(qdev) < 0) {
> + object_unref(OBJECT(qdev));
> qerror_report(QERR_DEVICE_INIT_FAILED, driver);
> return NULL;
> }
>
Reviewed-by: Paolo Bonzini <address@hidden>
- [Qemu-devel] [PATCH 0/6] qdev and blockdev refcount leak fixes, Stefan Hajnoczi, 2013/09/10
- [Qemu-devel] [PATCH 3/6] libqtest: rename qmp() to qmp_discard_response(), Stefan Hajnoczi, 2013/09/10
- [Qemu-devel] [PATCH 4/6] libqtest: add qmp(fmt, ...) -> QDict* function, Stefan Hajnoczi, 2013/09/10
- [Qemu-devel] [PATCH 5/6] blockdev-test: add test case for drive_add duplicate IDs, Stefan Hajnoczi, 2013/09/10
- [Qemu-devel] [PATCH 6/6] qdev-monitor-test: add device_add leak test cases, Stefan Hajnoczi, 2013/09/10