This is a note to let you know that I've just added the patch titled s390/vmem: fix identity mapping to the 3.18-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: s390-vmem-fix-identity-mapping.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c34a69059d7876e0793eb410deedfb08ccb22b02 Mon Sep 17 00:00:00 2001 From: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Date: Tue, 10 May 2016 12:10:22 +0200 Subject: s390/vmem: fix identity mapping From: Heiko Carstens <heiko.carstens@xxxxxxxxxx> commit c34a69059d7876e0793eb410deedfb08ccb22b02 upstream. The identity mapping is suboptimal for the last 2GB frame. The mapping will be established with a mix of 4KB and 1MB mappings instead of a single 2GB mapping. This happens because of a off-by-one bug introduced with commit 50be63450728 ("s390/mm: Convert bootmem to memblock"). Currently the identity mapping looks like this: 0x0000000080000000-0x0000000180000000 4G PUD RW 0x0000000180000000-0x00000001fff00000 2047M PMD RW 0x00000001fff00000-0x0000000200000000 1M PTE RW With the bug fixed it looks like this: 0x0000000080000000-0x0000000200000000 6G PUD RW Fixes: 50be63450728 ("s390/mm: Convert bootmem to memblock") Signed-off-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Jean Delvare <jdelvare@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/s390/mm/vmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -378,7 +378,7 @@ void __init vmem_map_init(void) ro_end = (unsigned long)&_eshared & PAGE_MASK; for_each_memblock(memory, reg) { start = reg->base; - end = reg->base + reg->size - 1; + end = reg->base + reg->size; if (start >= ro_end || end <= ro_start) vmem_add_mem(start, end - start, 0); else if (start >= ro_start && end <= ro_end) Patches currently in stable-queue which might be from heiko.carstens@xxxxxxxxxx are queue-3.18/s390-vmem-fix-identity-mapping.patch