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| author | Michael Holzheu <holzheu@linux.vnet.ibm.com> | 2014-01-30 16:14:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-22 10:32:45 -0800 |
| commit | 021139f22c744a254870dcb23b326037a32a1aa7 (patch) | |
| tree | d8136577e50f76a00676a4675d0b793ba506e294 /arch/s390 | |
| parent | fb11ab59b2999e2afee7c7fcd3687bf07b2fc988 (diff) | |
| download | lwn-021139f22c744a254870dcb23b326037a32a1aa7.tar.gz lwn-021139f22c744a254870dcb23b326037a32a1aa7.zip | |
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 <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/mm/page-states.c | 10 |
1 files changed, 10 insertions, 0 deletions
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 <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" |