The nid member of struct memory_block is a 4-byte integer, but read and printed as a 8-byte integer on 64-bit machines. Without the patch, the option displays wrong NIDs.

crash> kmem -n ... MEM_BLOCK NAME PHYSICAL RANGE NODE STATE START_SECTION_NO ffff9edeff2b9400 memory0 0 - 7fffffff 14195095130662240256 ONLINE 0 ffff9edeff2bb400 memory2 100000000 - 17fffffff 14195094718345379840 ONLINE 32 The issue seems to appear on Linux 5.12 and later kernels that contain commit e9a2e48e8704c ("drivers/base/memory: don't store phys_device in memory blocks"), which changed the arrangement of the members of struct memory_block. Signed-off-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; --- memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/memory.c b/memory.c index 8c6bbe409922..600f2de336d9 100644 --- a/memory.c +++ b/memory.c @@ -17564,13 +17564,13 @@ print_memory_block(ulong memory_block) if (MEMBER_EXISTS("memory_block", "nid")) { readmem(memory_block + OFFSET(memory_block_nid), KVADDR, &nid, - sizeof(void *), "memory_block nid", FAULT_ON_ERROR); + sizeof(int), "memory_block nid", FAULT_ON_ERROR); fprintf(fp, " %s %s %s %s %s %s\n", mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, MKSTR(memory_block)), mkstring(buf2, 12, CENTER, name), parangebuf, - mkstring(buf5, strlen("NODE"), CENTER|LONG_DEC, + mkstring(buf5, strlen("NODE"), CENTER|INT_DEC, MKSTR(nid)), mkstring(buf6, strlen("OFFLINE"), LJUST, statebuf), -- 2.27.0