Patch "virtio: 9p: correctly pass physical address to userspace for high pages" has been added to the 3.4-stable tree

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

virtio: 9p: correctly pass physical address to userspace for high pages

to the 3.4-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-9p-correctly-pass-physical-address-to-userspace-for-high-pages.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Will Deacon <[email protected]>
Date: Fri, 19 Oct 2012 14:03:32 +0100
Subject: virtio: 9p: correctly pass physical address to userspace for high pages

From: Will Deacon <[email protected]>

commit 30d395b124c51db66d9f3ba0611cd62021afc392 upstream.

commit b9cdc88df8e63e81c723b82c286fc97f5d0dc325 upstream.

When using a virtio transport, the 9p net device may pass the physical address of a kernel buffer to userspace via a scatterlist inside a virtqueue. If the kernel buffer is mapped outside of the linear mapping (e.g. highmem), then virt_to_page will return a bogus value and we will populate the scatterlist with junk.

This patch uses kmap_to_page when populating the page array for a kernel buffer.

---
 net/9p/trans_virtio.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -39,6 +39,7 @@
 #include <linux/inet.h>
 #include <linux/idr.h>
 #include <linux/file.h>
+#include <linux/highmem.h>
 #include <linux/slab.h>
 #include <net/9p/9p.h>
 #include <linux/parser.h>

@@ -325,7 +326,7 @@ static int p9_get_mapped_pages(struct vi
 		int count = nr_pages;
 		while (nr_pages) {
 			s = rest_of_page(data);
-			pages[index++] = virt_to_page(data);
+			pages[index++] = kmap_to_page(data);
 			data += s;
 			nr_pages--;
 		}

Patches currently in stable-queue which might be from [email protected] are

queue-3.4/usb-avoid-runtime-suspend-loops-for-hcds-that-can-t-handle-suspend-resume.patch queue-3.4/mm-highmem-export-kmap_to_page-for-modules.patch queue-3.4/virtio-9p-correctly-pass-physical-address-to-userspace-for-high-pages.patch