Messages in this thread Patch in this message | | | From | Kamal Mostafa <> | Subject | [PATCH 3.8 25/67] s390/dump: Fix dump memory detection | Date | Mon, 3 Mar 2014 10:55:13 -0800 |
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3.8.13.19 -stable review patch. If anyone has any objections, please let me know.
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From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
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 <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/s390/mm/page-states.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index a90d45e..27c50f4 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -12,6 +12,8 @@ #include <linux/mm.h> #include <linux/gfp.h> #include <linux/init.h> +#include <asm/setup.h> +#include <asm/ipl.h> #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" -- 1.8.3.2
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