root@odroid64-pre:~/crash-7.1.4# ./crash /proc/kcore crash 7.1.4 Copyright (C) 2002-2015 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005, 2011 NEC Corporation Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. This program is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Enter "help copying" to see the conditions. This program has absolutely no warranty. Enter "help warranty" for details. GNU gdb (GDB) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "aarch64-unknown-linux-gnu"... crash: seek error: kernel virtual address: ffffffc000ffe000 type: "pmd page" On Tue, Mar 8, 2016 at 2:27 PM, Dave Anderson <anderson(a)redhat.com&gt; wrote: > ----- Original Message ----- > > root@odroid64-pre:~/crash-7.1.4# ./crash --minimal > > crash> rd linux_banner 30 > > ffffffc00186a090: 0000001600000102 0000000000005018 .........P...... > > ffffffc00186a0a0: 00000000000115f9 0000001600000102 ................ > > ffffffc00186a0b0: 0000000000003e11 0000000000011606 .>.............. > > ffffffc00186a0c0: 0000001600000102 00000000000048d4 .........H...... > > ffffffc00186a0d0: 0000000000011614 0000001600000102 ................ > > ffffffc00186a0e0: 000000000000c2f1 0000000000011648 ........H....... > > ffffffc00186a0f0: 0000001600000102 00000000000048d4 .........H...... > > ffffffc00186a100: 0000000000011656 0000001600000102 V............... > > ffffffc00186a110: 0000000000009225 000000000001167d %.......}....... > > ffffffc00186a120: 0000001600000102 000000000000080f ................ > > ffffffc00186a130: 0000000000011688 0000001600000102 ................ > > ffffffc00186a140: 0000000000006e9f 0000000000011695 .n.............. > > ffffffc00186a150: 0000001600000102 000000000000619c .........a...... > > ffffffc00186a160: 00000000000116a2 0000001600000102 ................ > > ffffffc00186a170: 000000000000574a 00000000000116af JW.............. > > crash> > crash> help -m | grep -e page_offset -e phys_offset > > page_offset: ffffffc000000000 > > phys_offset: 1000000 > > > debug: 4 > > crash> rd linux_banner > > <addr: ffffffc00186a090 count: 1 flag: 490 (KVADDR)> > <readmem: ffffffc00186a090, KVADDR, "64-bit KVADDR", 8, (FOE), > 7ff6123398> > <read_dev_mem: addr: ffffffc00186a090 paddr: 286a090 cnt: 8> > ffffffc00186a090: 0000001600000102 ........ > > crash> > > > >Are there more than one "System RAM" sections in your /proc/iomem? > > Just one, the specs on this arm64 board are 2gb of ram > > sparse memory is configured. > > root@odroid64-pre:~/linux# grep -i sparse .config > > CONFIG_SPARSE_IRQ=y > > CONFIG_ARCH_SPARSEMEM_ENABLE=y > > CONFIG_ARCH_SPARSEMEM_DEFAULT=y > > CONFIG_SPARSEMEM_MANUAL=y > > CONFIG_SPARSEMEM=y > > CONFIG_SPARSEMEM_EXTREME=y > > CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y > > CONFIG_SPARSEMEM_VMEMMAP=y > > # CONFIG_INPUT_SPARSEKMAP is not set > > # CONFIG_SPARSE_RCU_POINTER is not set > > > root@odroid64-pre:~/crash-7.1.4# cat /proc/iomem > > 01000000-0fffffff : System RAM > > 01080000-01b21e83 : Kernel code > > 01bff000-01ffefff : Kernel data > > 10200000-77ffffff : System RAM > > c11084c0-c11084d3 : c11084c0.serial > > c1108500-c110851f : /i2c@c1108500 > > c1108680-c11086af : c1108680.saradc > > c11087c0-c11087df : /i2c@c11087c0 > > c1109880-c110988f : /pinmux > > c8013000-c80137ff : /mhu@c883c400 > > c8100014-c810001b : mux > > c8100024-c810002b : gpio > > c810002c-c810002f : pull > > c81004c0-c81004d3 : c81004c0.serial > > c8834120-c8834133 : pull-enable > > c8834430-c883446f : gpio > > c88344b0-c88344d7 : mux > > c88344e8-c88344fb : pull > > c8834540-c8834547 : /ethernet@0xc9410000 > > c8838000-c88383ff : c8838000.canvas > > c883c3d8-c883c3df : c1108680.saradc > > c883c400-c883c44b : /mhu@c883c400 > > c9410000-c941ffff : /ethernet@0xc9410000 > > > I backported about 15 arm64 patches from upstream to the 3.14 kernel we > are on and > > while doing so noticed a few patches regarding PTE calculations > > (I would have to go back and see if any would apply) > > Most appeared to be part of bigger changes to the memory layout > > > So should I focus on those arm64 PTE and virt patches? I wondered about > that but > > why would the kernel boot if those were screwed up... > For the simple unity-mapped kernel virtual addresses that we're dealing > with > at this early stage of the crash session, any PTE stuff wouldn't be > involved. > That would only come into play later on when translating kernel module and > vmalloc() > addresses. I don't know how any virt patches would affect anything at > this early > stage. > Anyway, everything looks "normal" above, except of course, the data that > gets > read. Did you try "crash /proc/kcore"? > Dave > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility

4k pages with 3-level PTE I did not backport any of the support for deeper level PTE's or larger page sizes no_modules works like a champ root@odroid64-pre:~/crash-7.1.4# ./crash /proc/kcore --no_modules crash 7.1.4 Copyright (C) 2002-2015 Red Hat, Inc. Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation Copyright (C) 1999-2006 Hewlett-Packard Co Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. Copyright (C) 2005, 2011 NEC Corporation Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. This program is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Enter "help copying" to see the conditions. This program has absolutely no warranty. Enter "help warranty" for details. GNU gdb (GDB) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "aarch64-unknown-linux-gnu"... WARNING: no kernel module access KERNEL: /lib/modules/3.14.29+/build/vmlinux DUMPFILE: /proc/kcore CPUS: 4 DATE: Tue Mar 8 15:15:26 2016 UPTIME: 05:23:46 LOAD AVERAGE: 0.67, 0.36, 0.19 TASKS: 207 NODENAME: odroid64-pre RELEASE: 3.14.29+ VERSION: #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 MACHINE: aarch64 (unknown Mhz) MEMORY: 1.9 GB PID: 8000 COMMAND: "crash" TASK: ffffffc05c298c00 [THREAD_INFO: ffffffc05857c000] CPU: 1 STATE: TASK_RUNNING (ACTIVE) crash root@odroid64-pre:~/crash-7.1.4# ./crash /proc/kcore -d8 crash 7.1.4 find_booted_kernel: check: /lib/modules/3.14.29+/build/vmlinux find_booted_kernel: found: /lib/modules/3.14.29+/build/vmlinux get_live_memory_source: /proc/kcore proc_kcore_data: flags: 0 (KCORE_LOCAL|KCORE_ELF64) segments: 6 elf_header: c71bb0 elf64: c71bb0 load64: c71c28 elf32: 0 load32: 0 ... continues like this a while ... /proc/version: Linux version 3.14.29+ (root@odroid64-pre) (gcc version 5.3.1 20160225 (Ubuntu/Linaro 5.3.1-10ubuntu2) ) #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 /lib/modules/3.14.29+/build/vmlinux: Linux version 3.14.29+ (root@odroid64-pre) (gcc version 5.3.1 20160225 (Ubuntu/Linaro 5.3.1-10ubuntu2) ) #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 readmem: read_proc_kcore() -> /proc/kcore VA_BITS: 39 using 1000000 as phys_offset gdb /lib/modules/3.14.29+/build/vmlinux GNU gdb (GDB) 7.6 Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "aarch64-unknown-linux-gnu"... GETBUF(248 -> 0) GETBUF(1500 -> 1) FREEBUF(1) FREEBUF(0) <readmem: ffffffc001874510, KVADDR, "kernel_config_data", 32768, (ROE), 17e0a60<read_proc_kcore: addr: ffffffc001874510 paddr: 2874510 cnt: 2800<read_proc_kcore: addr: ffffffc001875000 paddr: 2875000 cnt: 4096<read_proc_kcore: addr: ffffffc001876000 paddr: 2876000 cnt: 4096<read_proc_kcore: addr: ffffffc001877000 paddr: 2877000 cnt: 4096<read_proc_kcore: addr: ffffffc001878000 paddr: 2878000 cnt: 4096<read_proc_kcore: addr: ffffffc001879000 paddr: 2879000 cnt: 4096<read_proc_kcore: addr: ffffffc00187a000 paddr: 287a000 cnt: 4096<read_proc_kcore: addr: ffffffc00187b000 paddr: 287b000 cnt: 4096<read_proc_kcore: addr: ffffffc00187c000 paddr: 287c000 cnt: 1296# # Automatically generated file; DO NOT EDIT. # Linux/arm64 3.14.29 Kernel Configuration ... skip kernel config ... GETBUF(248 -> 0) FREEBUF(0) GETBUF(8 -> 0) <readmem: ffffffc00186fd80, KVADDR, "cpu_possible_mask", 8, (FOE), 7ffced02f0<read_proc_kcore: addr: ffffffc00186fd80 paddr: 286fd80 cnt: 8<readmem: ffffffc001cd9988, KVADDR, "possible", 8, (ROE), c14b08<read_proc_kcore: addr: ffffffc001cd9988 paddr: 2cd9988 cnt: 8cpu_possible_mask: cpus: 0 1 2 3 <readmem: ffffffc00186fd70, KVADDR, "cpu_present_mask", 8, (FOE), 7ffced02f0<read_proc_kcore: addr: ffffffc00186fd70 paddr: 286fd70 cnt: 8<readmem: ffffffc001cd9980, KVADDR, "present", 8, (ROE), c14b08<read_proc_kcore: addr: ffffffc001cd9980 paddr: 2cd9980 cnt: 8 cpu_present_mask: cpus: 0 1 2 3 <readmem: ffffffc00186fd78, KVADDR, "cpu_online_mask", 8, (FOE), 7ffced02f0<read_proc_kcore: addr: ffffffc00186fd78 paddr: 286fd78 cnt: 8<readmem: ffffffc001cd9978, KVADDR, "online", 8, (ROE), c14b08<read_proc_kcore: addr: ffffffc001cd9978 paddr: 2cd9978 cnt: 8 cpu_online_mask: cpus: 0 1 2 3 <readmem: ffffffc00186fd68, KVADDR, "cpu_active_mask", 8, (FOE), 7ffced02f0<read_proc_kcore: addr: ffffffc00186fd68 paddr: 286fd68 cnt: 8<readmem: ffffffc001cd9998, KVADDR, "active", 8, (ROE), c14b08<read_proc_kcore: addr: ffffffc001cd9998 paddr: 2cd9998 cnt: 8 cpu_active_mask: cpus: 0 1 2 3 ..... skip <readmem: ffffffc001d61238, KVADDR, "timekeeper xtime_sec", 8, (ROE), 7ffced03b8<read_proc_kcore: addr: ffffffc001d61238 paddr: 2d61238 cnt: 8xtime timespec.tv_sec: 56df41b3: Tue Mar 8 15:18:43 2016 <readmem: ffffffc001c0dbac, KVADDR, "init_uts_ns", 390, (ROE), bb208c<read_proc_kcore: addr: ffffffc001c0dbac paddr: 2c0dbac cnt: 390utsname: sysname: Linux nodename: odroid64-pre release: 3.14.29+ version: #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 machine: aarch64 domainname: (none) base kernel version: 3.14.29 <readmem: ffffffc00186a090, KVADDR, "accessible check", 8, (ROE|Q), 7ffcecfa70<read_proc_kcore: addr: ffffffc00186a090 paddr: 286a090 cnt: 8<readmem: ffffffc00186a090, KVADDR, "read_string characters", 1499, (ROE|Q), 7ffcecfde8<read_proc_kcore: addr: ffffffc00186a090 paddr: 286a090 cnt: 1499linux_banner: Linux version 3.14.29+ (root@odroid64-pre) (gcc version 5.3.1 20160225 (Ubuntu/Linaro 5.3.1-10ubuntu2) ) #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 verify_namelist: live memory /proc/version: Linux version 3.14.29+ (root@odroid64-pre) (gcc version 5.3.1 20160225 (Ubuntu/Linaro 5.3.1-10ubuntu2) ) #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 /lib/modules/3.14.29+/build/vmlinux: Linux version 3.14.29+ (root@odroid64-pre) (gcc version 5.3.1 20160225 (Ubuntu/Linaro 5.3.1-10ubuntu2) ) #1 SMP PREEMPT Tue Mar 8 01:06:35 CST 2016 <readmem: ffffffc001db2da8, KVADDR, "__per_cpu_offset", 32, (FOE), bb2238<read_proc_kcore: addr: ffffffc001db2da8 paddr: 2db2da8 cnt: 32GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) GNU_GET_DATATYPE[runqueue]: returned via gdb_error_hook (1 buffer in use) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) GNU_GET_DATATYPE[runqueue]: returned via gdb_error_hook (1 buffer in use) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) ^^^^ now repeats gdb_error_hook (1 buffer in use) for quite a while kernel NR_CPUS: 4 <readmem: ffffffc001c33208, KVADDR, "init_mm.pgd", 8, (ROE), 7ffced83d0<read_proc_kcore: addr: ffffffc001c33208 paddr: 2c33208 cnt: 8<readmem: ffffffc001db2e78, KVADDR, "high_memory", 8, (FOE), bc6368<read_proc_kcore: addr: ffffffc001db2e78 paddr: 2db2e78 cnt: 8GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) PAGESIZE=4096 mem_section_size = 32 NR_SECTION_ROOTS = 4 NR_MEM_SECTIONS = 1024 SECTIONS_PER_ROOT = 256 SECTION_ROOT_MASK = 0xff PAGES_PER_SECTION = 262144 <readmem: ffffffc001db4a80, KVADDR, "memory section root table", 32, (FOE), 2ff3390<read_proc_kcore: addr: ffffffc001db4a80 paddr: 2db4a80 cnt: 32<readmem: ffffffc001db2bc8, KVADDR, "totalram_pages", 8, (FOE), bc6388<read_proc_kcore: addr: ffffffc001db2bc8 paddr: 2db2bc8 cnt: 8<readmem: ffffffc001db2e88, KVADDR, "max_mapnr", 8, (FOE), bc63a0<read_proc_kcore: addr: ffffffc001db2e88 paddr: 2db2e88 cnt: 8<readmem: ffffffc001db47f4, KVADDR, "nr_swapfiles", 4, (FOE), bc6430<read_proc_kcore: addr: ffffffc001db47f4 paddr: 2db47f4 cnt: 4GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) FREEBUF(0) GETBUF(248 -> 0) GNU_GET_DATATYPE[free_area_struct]: returned via gdb_error_hook (1 buffer in use) .... skip repeats <readmem: ffffffc001c2f548, KVADDR, "node_online_map", 8, (ROE|Q), 41eede0<read_proc_kcore: addr: ffffffc001c2f548 paddr: 2c2f548 cnt: 8node_online_map: [1] -> nodes online: 1 .... skip repeats <readmem: ffffffc001cd03d8, KVADDR, "pglist node_id", 4, (FOE), 7ffced6568<read_proc_kcore: addr: ffffffc001cd03d8 paddr: 2cd03d8 cnt: 4<readmem: ffffffc001cd03c0, KVADDR, "pglist node_start_pfn", 8, (FOE), 7ffced65a0<read_proc_kcore: addr: ffffffc001cd03c0 paddr: 2cd03c0 cnt: 8<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc001cd03d0, KVADDR, "pglist node_spanned_pages", 8, (FOE), 7ffced65b0<read_proc_kcore: addr: ffffffc001cd03d0 paddr: 2cd03d0 cnt: 8<readmem: ffffffc001cd03c8, KVADDR, "pglist node_present_pages", 8, (FOE), 7ffced65b8<read_proc_kcore: addr: ffffffc001cd03c8 paddr: 2cd03c8 cnt: 8node_table[0]: id: 0 pgdat: ffffffc001ccf280 size: 487424 present: 486912 mem_map: ffffff8040058000 start_paddr: 1000000 start_mapnr: 4096 zone 0 at ffffffc001ccf280 <readmem: ffffffc001ccfaa8, KVADDR, "zone spanned_pages", 8, (FOE), 7ffced65c8<read_proc_kcore: addr: ffffffc001ccfaa8 paddr: 2ccfaa8 cnt: 8<readmem: ffffffc001ccf8d8, KVADDR, "zone[_struct] free_pages", 8, (FOE), 7ffced65c0<read_proc_kcore: addr: ffffffc001ccf8d8 paddr: 2ccf8d8 cnt: 8<readmem: ffffffc001ccfac8, KVADDR, "zone[_struct] name", 8, (FOE), 7ffced6610<read_proc_kcore: addr: ffffffc001ccfac8 paddr: 2ccfac8 cnt: 8<readmem: ffffffc001a38168, KVADDR, "read_string characters", 1499, (ROE|Q), 7ffced6638<read_proc_kcore: addr: ffffffc001a38168 paddr: 2a38168 cnt: 1499<readmem: ffffffc001ccfaa0, KVADDR, "node_zones zone_start_pfn", 8, (FOE), 7ffced65f8<read_proc_kcore: addr: ffffffc001ccfaa0 paddr: 2ccfaa0 cnt: 8<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16zone 1 at ffffffc001ccfb00 <readmem: ffffffc001cd0328, KVADDR, "zone spanned_pages", 8, (FOE), 7ffced65c8<read_proc_kcore: addr: ffffffc001cd0328 paddr: 2cd0328 cnt: 8<readmem: ffffffc001cd0158, KVADDR, "zone[_struct] free_pages", 8, (FOE), 7ffced65c0<read_proc_kcore: addr: ffffffc001cd0158 paddr: 2cd0158 cnt: 8<readmem: ffffffc001cd0348, KVADDR, "zone[_struct] name", 8, (FOE), 7ffced6610<read_proc_kcore: addr: ffffffc001cd0348 paddr: 2cd0348 cnt: 8<readmem: ffffffc001a38500, KVADDR, "read_string characters", 1499, (ROE|Q), 7ffced6638<read_proc_kcore: addr: ffffffc001a38500 paddr: 2a38500 cnt: 1499<readmem: ffffffc001cd0320, KVADDR, "node_zones zone_start_pfn", 8, (FOE), 7ffced65f8<read_proc_kcore: addr: ffffffc001cd0320 paddr: 2cd0320 cnt: 8<readmem: ffffffc001cd03d8, KVADDR, "pglist node_id", 4, (FOE), 7ffced6568<read_proc_kcore: addr: ffffffc001cd03d8 paddr: 2cd03d8 cnt: 4<readmem: ffffffc001cd03c0, KVADDR, "pglist node_start_pfn", 8, (FOE), 7ffced65a0<read_proc_kcore: addr: ffffffc001cd03c0 paddr: 2cd03c0 cnt: 8<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc001cd03d0, KVADDR, "pglist node_spanned_pages", 8, (FOE), 7ffced65b0<read_proc_kcore: addr: ffffffc001cd03d0 paddr: 2cd03d0 cnt: 8<readmem: ffffffc001cd03c8, KVADDR, "pglist node_present_pages", 8, (FOE), 7ffced65b8<read_proc_kcore: addr: ffffffc001cd03c8 paddr: 2cd03c8 cnt: 8NODE SIZE PGLIST_DATA BOOTMEM_DATA NODE_ZONES 0 487424 ffffffc001ccf280 ---- ffffffc001ccf280 ffffffc001ccfb00 MEM_MAP START_PADDR START_MAPNR ffffff8040058000 1000000 4096 ZONE NAME SIZE MEM_MAP START_PADDR START_MAPNR zone 0 at ffffffc001ccf280 <readmem: ffffffc001ccfaa8, KVADDR, "zone spanned_pages", 8, (FOE), 7ffced65c8<read_proc_kcore: addr: ffffffc001ccfaa8 paddr: 2ccfaa8 cnt: 8<readmem: ffffffc001ccf8d8, KVADDR, "zone[_struct] free_pages", 8, (FOE), 7ffced65c0<read_proc_kcore: addr: ffffffc001ccf8d8 paddr: 2ccf8d8 cnt: 8<readmem: ffffffc001ccfac8, KVADDR, "zone[_struct] name", 8, (FOE), 7ffced6610<read_proc_kcore: addr: ffffffc001ccfac8 paddr: 2ccfac8 cnt: 8<readmem: ffffffc001a38168, KVADDR, "read_string characters", 1499, (ROE|Q), 7ffced6638<read_proc_kcore: addr: ffffffc001a38168 paddr: 2a38168 cnt: 1499<readmem: ffffffc001ccfaa0, KVADDR, "node_zones zone_start_pfn", 8, (FOE), 7ffced65f8<read_proc_kcore: addr: ffffffc001ccfaa0 paddr: 2ccfaa0 cnt: 8<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16 0 Normal 487424 ffffff8040058000 1000000 4096 zone 1 at ffffffc001ccfb00 <readmem: ffffffc001cd0328, KVADDR, "zone spanned_pages", 8, (FOE), 7ffced65c8<read_proc_kcore: addr: ffffffc001cd0328 paddr: 2cd0328 cnt: 8<readmem: ffffffc001cd0158, KVADDR, "zone[_struct] free_pages", 8, (FOE), 7ffced65c0<read_proc_kcore: addr: ffffffc001cd0158 paddr: 2cd0158 cnt: 8<readmem: ffffffc001cd0348, KVADDR, "zone[_struct] name", 8, (FOE), 7ffced6610<read_proc_kcore: addr: ffffffc001cd0348 paddr: 2cd0348 cnt: 8<readmem: ffffffc001a38500, KVADDR, "read_string characters", 1499, (ROE|Q), 7ffced6638<read_proc_kcore: addr: ffffffc001a38500 paddr: 2a38500 cnt: 1499<readmem: ffffffc001cd0320, KVADDR, "node_zones zone_start_pfn", 8, (FOE), 7ffced65f8<read_proc_kcore: addr: ffffffc001cd0320 paddr: 2cd0320 cnt: 8 1 Movable 0 0 0 0 ------------------------------------------------------------------- NR SECTION CODED_MEM_MAP MEM_MAP PFN <readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16<readmem: ffffffc0741fe000, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe000 paddr: 751fe000 cnt: 16 0 ffffffc0741fe000 ffffff8040010000 ffffff8040010000 0 <readmem: ffffffc0741fe010, KVADDR, "memory section", 16, (FOE), 11e6810<read_proc_kcore: addr: ffffffc0741fe010 paddr: 751fe010 cnt: 16.... continues on this way a while GETBUF(248 -> 0) FREEBUF(0) <readmem: ffffffc001c27f58, KVADDR, "modules", 8, (FOE), bb1a88<read_proc_kcore: addr: ffffffc001c27f58 paddr: 2c27f58 cnt: 8GETBUF(528 -> 0) module: ffffffbffc081ad0 <readmem: ffffffbffc081ad0, KVADDR, "module struct", 528, (ROE|Q), c14b08<readmem: ffffffc001ffc000, KVADDR, "pgd page", 4096, (FOE), f41e90<read_proc_kcore: addr: ffffffc001ffc000 paddr: 2ffc000 cnt: 4096<readmem: ffffffc000ffe000, KVADDR, "pmd page", 4096, (FOE), f42ea0<read_proc_kcore: addr: ffffffc000ffe000 paddr: 1ffe000 cnt: 4096crash: seek error: kernel virtual address: ffffffc000ffe000 type: "pmd page" root@odroid64-pre:~/crash-7.1.4# On Tue, Mar 8, 2016 at 3:02 PM, Dave Anderson <anderson(a)redhat.com&gt; wrote: > ----- Original Message ----- > > root@odroid64-pre:~/crash-7.1.4# ./crash /proc/kcore > > > crash 7.1.4 > > Copyright (C) 2002-2015 Red Hat, Inc. > > Copyright (C) 2004, 2005, 2006, 2010 IBM Corporation > > Copyright (C) 1999-2006 Hewlett-Packard Co > > Copyright (C) 2005, 2006, 2011, 2012 Fujitsu Limited > > Copyright (C) 2006, 2007 VA Linux Systems Japan K.K. > > Copyright (C) 2005, 2011 NEC Corporation > > Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc. > > Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc. > > This program is free software, covered by the GNU General Public License, > > and you are welcome to change it and/or distribute copies of it under > > certain conditions. Enter "help copying" to see the conditions. > > This program has absolutely no warranty. Enter "help warranty" for > details. > > > GNU gdb (GDB) 7.6 > > Copyright (C) 2013 Free Software Foundation, Inc. > > License GPLv3+: GNU GPL version 3 or later < > http://gnu.org/licenses/gpl.html > > > > This is free software: you are free to change and redistribute it. > > There is NO WARRANTY, to the extent permitted by law. Type "show copying" > > and "show warranty" for details. > > This GDB was configured as "aarch64-unknown-linux-gnu"... > > > crash: seek error: kernel virtual address: ffffffc000ffe000 type: "pmd > page" > So if you did a "crash -d8", you would see that you got significantly > farther than you did with /dev/mem, and where I think from the seek error > type above, perhaps as far as getting into the module initialization phase. > Although, if I run with -d8, I never see the "pmd page" type being read, > so I'm not sure where that's coming from. > Anyway, try -d8, and you should see legitimate stuff read from > "linux_banner" > and the utsname structure, and you should see how far you got. > You might even be able to get to a crash> prompt by running: > $ crash /proc/kcore --no_modules > which would avoid doing any kind of PTE-requiring address translation. > In any case, there's something about the /dev/mem driver that I'm not aware > of. I'm pretty sure that that when I did the initial arm64 port for crash, > that I *did* use /dev/mem at first, because Red Hat hadn't gotten around to > restricting it yet. > Anyway, if you're at the module initialization stage, then the PTE > stuff comes into play. Note that crash currently only supports ARM64 > systems configured with 64k pages with 2-level PTEs or 4k pages with > 3-level PTEs. How is your system configured? > Dave > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://www.redhat.com/mailman/listinfo/crash-utility