From 312cdf57ee8b7ef9ae1967e243a770dc5557af05 Mon Sep 17 00:00:00 2001 From: Michael Holzheu Date: Thu, 30 Jan 2014 16:14:02 +0100 Subject: s390/dump: Fix dump memory detection commit d7736ff5be31edaa4fe5ab62810c64529a24b149 upstream. Dumps created by kdump or zfcpdump can contain invalid memory holes when dumping z/VM systems that have memory pressure. For example: # zgetdump -i /proc/vmcore. Memory map: 0000000000000000 - 0000000000bfffff (12 MB) 0000000000e00000 - 00000000014fffff (7 MB) 000000000bd00000 - 00000000f3bfffff (3711 MB) The memory detection function find_memory_chunks() issues tprot to find valid memory chunks. In case of CMM it can happen that pages are marked as unstable via set_page_unstable() in arch_free_page(). If z/VM has released that pages, tprot returns -EFAULT and indicates a memory hole. So fix this and switch off CMM in case of kdump or zfcpdump. Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman --- arch/s390/mm/page-states.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/s390') diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index a90d45e9dfb0..27c50f4d90cb 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -12,6 +12,8 @@ #include #include #include +#include +#include #define ESSA_SET_STABLE 1 #define ESSA_SET_UNUSED 2 @@ -41,6 +43,14 @@ void __init cmma_init(void) if (!cmma_flag) return; + /* + * Disable CMM for dump, otherwise the tprot based memory + * detection can fail because of unstable pages. + */ + if (OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP) { + cmma_flag = 0; + return; + } asm volatile( " .insn rrf,0xb9ab0000,%1,%1,0,0\n" "0: la %0,0\n" -- cgit v1.2.3