3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: YASUAKI ISHIMATSU yasu.isimatu@gmail.com
commit 1dd2bfc86818ddbc95f98e312e7704350223fd7d upstream.
pfn_to_section_nr() and section_nr_to_pfn() are defined as macro. pfn_to_section_nr() has no issue even if it is defined as macro. But section_nr_to_pfn() has overflow issue if sec is defined as int.
section_nr_to_pfn() just shifts sec by PFN_SECTION_SHIFT. If sec is defined as unsigned long, section_nr_to_pfn() returns pfn as 64 bit value. But if sec is defined as int, section_nr_to_pfn() returns pfn as 32 bit value.
__remove_section() calculates start_pfn using section_nr_to_pfn() and scn_nr defined as int. So if hot-removed memory address is over 16TB, overflow issue occurs and section_nr_to_pfn() does not calculate correct pfn.
To make callers use proper arg, the patch changes the macros to inline functions.
Fixes: 815121d2b5cd ("memory_hotplug: clear zone when removing the memory") Link: http://lkml.kernel.org/r/e643a387-e573-6bbf-d418-c60c8ee3d15e@gmail.com Signed-off-by: Yasuaki Ishimatsu isimatu.yasuaki@jp.fujitsu.com Acked-by: Michal Hocko mhocko@suse.com Cc: Xishi Qiu qiuxishi@huawei.com Cc: Reza Arbab arbab@linux.vnet.ibm.com Cc: Vlastimil Babka vbabka@suse.cz Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ben Hutchings ben@decadent.org.uk --- include/linux/mmzone.h | 10 ++++++++-- mm/memory_hotplug.c | 2 +- 2 files changed, 9 insertions(+), 3 deletions(-)
--- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1094,8 +1094,14 @@ static inline unsigned long early_pfn_to #error Allocator MAX_ORDER exceeds SECTION_SIZE #endif
-#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT) -#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT) +static inline unsigned long pfn_to_section_nr(unsigned long pfn) +{ + return pfn >> PFN_SECTION_SHIFT; +} +static inline unsigned long section_nr_to_pfn(unsigned long sec) +{ + return sec << PFN_SECTION_SHIFT; +}
#define SECTION_ALIGN_UP(pfn) (((pfn) + PAGES_PER_SECTION - 1) & PAGE_SECTION_MASK) #define SECTION_ALIGN_DOWN(pfn) ((pfn) & PAGE_SECTION_MASK) --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -735,7 +735,7 @@ static int __remove_section(struct zone return ret;
scn_nr = __section_nr(ms); - start_pfn = section_nr_to_pfn(scn_nr); + start_pfn = section_nr_to_pfn((unsigned long)scn_nr); __remove_zone(zone, start_pfn);
sparse_remove_one_section(zone, ms);