When trying to do 'cp /proc/vmcore ...', the kdump kernel MCA'ed. KDB showed me this backtrace: (it is really nice to have kdb working with kdump :)) Entering kdb (current=0xe000003032570000, pid 3519) on processor 0 due to KDB_ENTER() [0]kdb> bt Stack traceback for pid 3519 0xe000003032570000 3519 3502 0 0 R 0xe0000030325703a0 *cp 0xa00000010000c720 ia64_native_leave_kernel 0xa00000010047d770 __copy_user+0x570 args (0x600fffffff9f4fb4, 0xe000003000080000, 0xb04c) 0xa000000100061b70 copy_oldmem_page+0xb0 args (0xe000003000080000, 0x600fffffff9f4fb4, 0xb04c, 0x0, 0x1, 0xa00000010021c1c0, 0x50f, 0x3) 0xa00000010021c1c0 read_from_oldmem+0xe0 args (0x600fffffffa00000, 0x0, 0xe00000303257fe20, 0x1, 0xb04c, 0x300009, 0xb04c, 0xa00000010021c480, 0x50e) 0xa00000010021c480 read_vmcore+0x260 args (0xe0000030350de500, 0x600fffffffa00000, 0xb04c, 0xe00000303257fe38, 0xe000003037fa4e80, 0x0, 0x10000, 0xa00000010020a000, 0x48d) 0xa00000010020a000 proc_reg_read+0x120 args (0xe0000030350de500, 0x600fffffff9f0000, 0x10000, 0xe00000303257fe38, 0xfffffffffffffffb, 0xe0000030194f1440, 0xa00000010017f6f0, 0x50f, 0xa000000100fcc510) 0xa00000010017f6f0 vfs_read+0x1b0 args (0xe0000030350de500, 0x600fffffff9f0000, 0x10000, 0xe00000303257fe38, 0x0, 0x3, 0x0, 0xa00000010017fcf0, 0x793) 0xa00000010017fcf0 sys_read+0x70 args (0x3, 0x600fffffff9f0000, 0x10000, 0x10000, 0x4000000000007a80, 0xc000000000000916, 0x600000000000b370, 0x4, 0xe0000030350de538) 0xa00000010000c580 ia64_ret_from_syscall args (0x3, 0x600fffffff9f0000, 0x10000, 0x10000) 0xa000000000010720 __kernel_syscall_via_break args (0x3, 0x600fffffff9f0000, 0x10000, 0x10000) [0]kdb> The instruction that MCA'ed the system was trying to read from vmcore at address 0x3000080000. The address comes from the vmcore_list: <4>vmcore_init: elfcorehdr_addr=3037fc0000 <4>Printing vmcore_list... <4> paddr=307b8b0800, size=48c <4> paddr=307b8b1000, size=48c <4> paddr=30151da898, size=4bc <4> paddr=3014000000, size=825d90 <4> paddr=3000080000, size=380000 <===== this one <4> paddr=3003000000, size=3000000 <4> paddr=3006000000, size=e000000 <4> paddr=3014000000, size=1295000 <4> paddr=3015295000, size=2d6b000 <4> paddr=3038000000, size=41ef8000 <4> paddr=3079ef8000, size=4fc000 <4> paddr=307a3f4000, size=5e000 <4> paddr=307a452000, size=3ac000 <4> paddr=307b800000, size=1000 <4> paddr=307b801000, size=135000 <4> paddr=307b936000, size=6000 <4> paddr=307b93c000, size=2000 <4> paddr=307b93e000, size=6000 <4> paddr=307b944000, size=1000 <4> paddr=307b945000, size=b9000 <4> paddr=307b9fe000, size=35a000 <4> paddr=307bd92000, size=6c000 <4> paddr=307bdfe000, size=12000 <4> paddr=307be7e000, size=4000 <4>End of vmcore_list... However, memmap from efi indicated that memory region is not accessible (attribute is 1). Shell> memmap Type Start End # Pages Attributes PAL_code 0000000001000000-0000000001FFFFFF 0000000000001000 8000000000000009 MemMapIO 00000000FF800000-00000000FFFFFFFF 0000000000000800 8000000000000001 MemMapIO 0000000800000000-0000000FFFFFFFFF 0000000000800000 8000000000000001 Unusable 0000003000000000-000000300000FFFF 0000000000000010 0000000000000009 RT_data 0000003000010000-000000300007FFFF 0000000000000070 8000000000001001 BS_data 0000003000080000-00000030003FFFFF 0000000000000380 0000000000000001 RT_data 0000003000400000-0000003001FFFFFF 0000000000001C00 8000000000001009 RT_data 0000003002000000-0000003002FFFFFF 0000000000001000 8000000000000009 BS_data 0000003003000000-0000003005FFFFFF 0000000000003000 0000000000000009 available 0000003006000000-000000307A451FFF 0000000000074452 0000000000000009 BS_data 000000307A452000-000000307A7FDFFF 00000000000003AC 0000000000000009 RT_data 000000307A7FE000-000000307B7FFFFF 0000000000001002 8000000000000009 BS_data 000000307B800000-000000307B800FFF 0000000000000001 0000000000000009 available 000000307B801000-000000307B92BFFF 000000000000012B 0000000000000009 BS_data 000000307B92C000-000000307B943FFF 0000000000000018 0000000000000009 available 000000307B944000-000000307B944FFF 0000000000000001 0000000000000009 BS_data 000000307B945000-000000307B9FDFFF 00000000000000B9 0000000000000009 available 000000307B9FE000-000000307BD57FFF 000000000000035A 0000000000000009 RT_code 000000307BD58000-000000307BD91FFF 000000000000003A 8000000000000009 BS_code 000000307BD92000-000000307BDFDFFF 000000000000006C 0000000000000009 available 000000307BDFE000-000000307BE0FFFF 0000000000000012 0000000000000009 RT_code 000000307BE10000-000000307BE7DFFF 000000000000006E 8000000000000009 available 000000307BE7E000-000000307BE83FFF 0000000000000006 0000000000000009 RT_data 000000307BE84000-000000307BFFFFFF 000000000000017C 8000000000000009 MemPortIO 1FFFFFFFFC000000-1FFFFFFFFFFFFFFF 0000000000004000 8000000000000001 BS_code : 108 Pages (442,368) BS_data : 14,334 Pages (58,712,064) RT_code : 168 Pages (688,128) RT_data : 15,854 Pages (64,937,984) available : 477,424 Pages (1,955,528,704) Unusable : 16 Pages (65,536) MemMapIO : 8,390,656 Pages (34,368,126,976) MemPortIO : 16,384 Pages (67,108,864) PAL_code : 4,096 Pages (16,777,216) Total Memory: 1,999 MB (2,097,086,464) Bytes Shell> Again, the vmcore_list prints: (i added the debugging at the end of parse_crash_elf64_headers() routine in fs/proc/vmcore.c): <4>Printing vmcore_list... <4> paddr=307b8b0800, size=48c <4> paddr=307b8b1000, size=48c <4> paddr=30151da898, size=4bc <4> paddr=3014000000, size=825d90 <4> paddr=3000080000, size=380000 <===== this one ... Any input helping me speed up debugging is appreciated. Thanks. - jay