The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From a1eb03f546d651a8f39c7d0692b1f7f5b4e7e3cd Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Date: Sun, 4 Jan 2015 17:28:27 +0200 Subject: [PATCH] virtio_pci: document why we defer kfree The reason we defer kfree until release function is because it's a general rule for kobjects: kfree of the reference counter itself is only legal in the release function. Previous patch didn't make this clear, document this in code. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> diff --git a/drivers/virtio/virtio_pci_legacy.c b/drivers/virtio/virtio_pci_legacy.c index 4beaee384906..a5486e65e04b 100644 --- a/drivers/virtio/virtio_pci_legacy.c +++ b/drivers/virtio/virtio_pci_legacy.c @@ -216,6 +216,9 @@ static void virtio_pci_release_dev(struct device *_d) struct virtio_device *vdev = dev_to_virtio(_d); struct virtio_pci_device *vp_dev = to_vp_device(vdev); + /* As struct device is a kobject, it's not safe to + * free the memory (including the reference counter itself) + * until it's release callback. */ kfree(vp_dev); } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html