This is a note to let you know that I've just added the patch titled
xen-netfront: Remove BUGs on paged skb data which crosses a page boundary
to the 3.17-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:
xen-netfront-remove-bugs-on-paged-skb-data-which-crosses-a-page-boundary.patch
and it can be found in the queue-3.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 8d609725d4357f499e2103e46011308b32f53513 Mon Sep 17 00:00:00 2001
From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Date: Tue, 25 Nov 2014 20:28:24 -0600
Subject: xen-netfront: Remove BUGs on paged skb data which crosses a page boundary
From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
commit 8d609725d4357f499e2103e46011308b32f53513 upstream.
These BUGs can be erroneously triggered by frags which refer to
tail pages within a compound page. The data in these pages may
overrun the hardware page while still being contained within the
compound page, but since compound_order() evaluates to 0 for tail
pages the assertion fails. The code already iterates through
subsequent pages correctly in this scenario, so the BUGs are
unnecessary and can be removed.
Fixes: f36c374782e4 ("xen/netfront: handle compound page fragments on transmit")
Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx>
Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/xen-netfront.c | 5 -----
1 file changed, 5 deletions(-)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -496,9 +496,6 @@ static void xennet_make_frags(struct sk_
len = skb_frag_size(frag);
offset = frag->page_offset;
- /* Data must not cross a page boundary. */
- BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
-
/* Skip unused frames from start of page */
page += offset >> PAGE_SHIFT;
offset &= ~PAGE_MASK;
@@ -506,8 +503,6 @@ static void xennet_make_frags(struct sk_
while (len > 0) {
unsigned long bytes;
- BUG_ON(offset >= PAGE_SIZE);
-
bytes = PAGE_SIZE - offset;
if (bytes > len)
bytes = len;
Patches currently in stable-queue which might be from seth.forshee@xxxxxxxxxxxxx are
queue-3.17/xen-netfront-remove-bugs-on-paged-skb-data-which-crosses-a-page-boundary.patch
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