Patch "mm: use phys_addr_t for reserve_bootmem_region() arguments" has been added to the 4.5-stable tree

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

mm: use phys_addr_t for reserve_bootmem_region() arguments

to the 4.5-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:
mm-use-phys_addr_t-for-reserve_bootmem_region-arguments.patch
and it can be found in the queue-4.5 subdirectory.

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

From: Stefan Bader <[email protected]>
Date: Fri, 20 May 2016 16:58:38 -0700
Subject: mm: use phys_addr_t for reserve_bootmem_region() arguments

From: Stefan Bader <[email protected]>

commit 4b50bcc7eda4d3cc9e3f2a0aa60e590fedf728c5 upstream.

Since commit 92923ca3aace ("mm: meminit: only set page reserved in the memblock region") the reserved bit is set on reserved memblock regions. However start and end address are passed as unsigned long. This is only 32bit on i386, so it can end up marking the wrong pages reserved for ranges at 4GB and above.

This was observed on a 32bit Xen dom0 which was booted with initial memory set to a value below 4G but allowing to balloon in memory (dom0_mem=1024M for example). This would define a reserved bootmem region for the additional memory (for example on a 8GB system there was a reverved region covering the 4GB-8GB range). But since the addresses were passed on as unsigned long, this was actually marking all pages from 0 to 4GB as reserved.

---
 include/linux/mm.h |    2 +-
 mm/page_alloc.c    |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

@@ -1763,7 +1763,7 @@ extern void free_highmem_page(struct pag
 extern void adjust_managed_page_count(struct page *page, long count);
 extern void mem_init_print_info(const char *str);
 
-extern void reserve_bootmem_region(unsigned long start, unsigned long end);
+extern void reserve_bootmem_region(phys_addr_t start, phys_addr_t end);
 
 /* Free the reserved page into the buddy system, so it gets managed. */
 static inline void __free_reserved_page(struct page *page)

@@ -971,7 +971,7 @@ static inline void init_reserved_page(un
  * marks the pages PageReserved. The remaining valid pages are later
  * sent to the buddy page allocator.
  */
-void __meminit reserve_bootmem_region(unsigned long start, unsigned long end)
+void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
 {
 	unsigned long start_pfn = PFN_DOWN(start);
 	unsigned long end_pfn = PFN_UP(end);

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

queue-4.5/mm-use-phys_addr_t-for-reserve_bootmem_region-arguments.patch