From: Sasha Levin Date: Fri, 2 Jan 2015 19:47:40 +0000 (-0500) Subject: virtio_pci: defer kfree until release callback X-Git-Tag: fixes-v4.0-rc1~334^2~2 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=63bd62a08ca45a0c804c3c89777edc7f76a2d6da virtio_pci: defer kfree until release callback A struct device which has just been unregistered can live on past the point at which a driver decides to drop it's initial reference to the kobject gained on allocation. This implies that when releasing a virtio device, we can't free a struct virtio_device until the underlying struct device has been released, which might not happen immediately on device_unregister(). Unfortunately, this is exactly what virtio pci does: it has an empty release callback, and frees memory immediately after unregistering the device. This causes an easy to reproduce crash if CONFIG_DEBUG_KOBJECT_RELEASE it enabled. To fix, free the memory only once we know the device is gone in the release callback. Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin Signed-off-by: Michael S. Tsirkin --- Reading git-diff-tree failed