Messages in this thread | | | Date | Mon, 6 Jan 2014 11:00:33 +0000 | From | David Vrabel <> | Subject | Re: [Xen-devel] [PATCH 26/38] xen: xenbus: add missing put_device call |
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On 06/01/14 10:00, Ian Campbell wrote: > On Thu, 2014-01-02 at 13:53 +0000, David Vrabel wrote: >> On 19/12/13 15:03, Levente Kurusa wrote: >>> This is required so that we give up the last reference to the device. >>> >>> Signed-off-by: Levente Kurusa <levex@linux.com> >>> --- >>> drivers/xen/xenbus/xenbus_probe.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c >>> index 3c0a74b..4abb9ee 100644 >>> --- a/drivers/xen/xenbus/xenbus_probe.c >>> +++ b/drivers/xen/xenbus/xenbus_probe.c >>> @@ -465,8 +465,10 @@ int xenbus_probe_node(struct xen_bus_type *bus, >>> >>> /* Register with generic device framework. */ >>> err = device_register(&xendev->dev); >>> - if (err) >>> + if (err) { >>> + put_device(&xendev->dev); >>> goto fail; >>> + } >>> >>> return 0; >>> fail: >> >> There is a kfree(xendev) here so this introduces a double-free. > > How? put_device doesn't touch xendev itself, does it? It just drops the > ref on the dev member which is not separately dynamically allocated and > so not freed either.
Releasing all references to the struct device frees the containing structure via xenbus->dev.release. i.e., xenbus_dev_release() which does kfree(xendev).
David
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