Patch "xen: Fix page <-> pfn conversion on 32 bit systems" has been added to the 4.4-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
xen: Fix page <-> pfn conversion on 32 bit systems
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:
xen-fix-page-pfn-conversion-on-32-bit-systems.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 <[email protected]> know about it.
Quoted 1 line
From
60901df3aed230d4565dca003f11b6a95fbf30d9Mon Sep 17 00:00:00 2001
From: Ross Lagerwall <[email protected]>
Date: Thu, 17 Mar 2016 16:51:59 +0000
Subject: xen: Fix page <-> pfn conversion on 32 bit systems
From: Ross Lagerwall <[email protected]>
commit 60901df3aed230d4565dca003f11b6a95fbf30d9 upstream.
Commit 1084b1988d22dc165c9dbbc2b0e057f9248ac4db (xen: Add Xen specific page definition) caused a regression in 4.4.
The xen functions to convert between pages and pfns fail due to an overflow on systems where a physical address may not fit in an unsigned long (e.g. x86 32 bit PAE systems). Rework the conversion to avoid overflow. This should also result in simpler object code.
This bug manifested itself as disk corruption with Linux 4.4 when using blkfront in a Xen HVM x86 32 bit guest with more than 4 GiB of memory.
--- include/xen/page.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
include/xen/page.h +2 -2
@@ -15,9 +15,9 @@*/ #define xen_pfn_to_page (xen_pfn) \ - ((pfn_to_page(((unsigned long)(xen_pfn) << XEN_PAGE_SHIFT) >> PAGE_SHIFT))) + (pfn_to_page((unsigned long)(xen_pfn) >> (PAGE_SHIFT - XEN_PAGE_SHIFT)))#define page_to_xen_pfn (page) \ - (((page_to_pfn(page)) << PAGE_SHIFT) >> XEN_PAGE_SHIFT) + ((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT))#define XEN_PFN_PER_PAGE (PAGE_SIZE / XEN_PAGE_SIZE)
Patches currently in stable-queue which might be from [email protected] are
queue-4.4/xen-balloon-fix-crash-when-ballooning-on-x86-32-bit-pae.patch queue-4.4/xen-fix-page-pfn-conversion-on-32-bit-systems.patch