Patch "virtio_pci: fix use after free on release" has been added to the 4.4-stable tree

Patch "virtio_pci: fix use after free on release" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    virtio_pci: fix use after free on release

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio_pci-fix-use-after-free-on-release.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2989be09a8a9d62a785137586ad941f916e08f83 Mon Sep 17 00:00:00 2001
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Thu, 14 Jan 2016 16:00:41 +0200
Subject: virtio_pci: fix use after free on release

From: Michael S. Tsirkin <mst@redhat.com>

commit 2989be09a8a9d62a785137586ad941f916e08f83 upstream.

KASan detected a use-after-free error in virtio-pci remove code. In
virtio_pci_remove(), vp_dev is still used after being freed in
unregister_virtio_device() (in virtio_pci_release_dev() more
precisely).

To fix, keep a reference until cleanup is done.

Fixes: 63bd62a08ca4 ("virtio_pci: defer kfree until release callback")
Reported-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/virtio/virtio_pci_common.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -545,6 +545,7 @@ err_enable_device:
 static void virtio_pci_remove(struct pci_dev *pci_dev)
 {
 	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct device *dev = get_device(&vp_dev->vdev.dev);
 
 	unregister_virtio_device(&vp_dev->vdev);
 
@@ -554,6 +555,7 @@ static void virtio_pci_remove(struct pci
 		virtio_pci_modern_remove(vp_dev);
 
 	pci_disable_device(pci_dev);
+	put_device(dev);
 }
 
 static struct pci_driver virtio_pci_driver = {


Patches currently in stable-queue which might be from mst@redhat.com are

queue-4.4/virtio_pci-fix-use-after-free-on-release.patch
queue-4.4/virtio_balloon-fix-race-by-fill-and-leak.patch
queue-4.4/virtio_balloon-fix-race-between-migration-and-ballooning.patch