[Crash-utility] crash for live system fails to load - Ubuntu 16.10

Kaiwan N Billimoria kaiwan.billimoria at gmail.com
Mon Apr 17 01:51:16 UTC 2017


Hi,

I've been using crash for a while..
Strangely, on Ubuntu (and Lubuntu) 16.10, I face the issue described below:

$ cat /etc/issue
Ubuntu 16.10 \n \l

$ uname -r
4.8.0-46-generic
$ cat /proc/version
Linux version 4.8.0-46-generic (buildd at lcy01-16) (gcc version 6.2.0
20161005 (Ubuntu 6.2.0-5ubuntu12) ) #49-Ubuntu SMP Fri Mar 31 13:57:14
UTC 2017
$ cat /proc/version_signature
Ubuntu 4.8.0-46.49-generic 4.8.17
$

So I download the dbgsym package for this kernel as:
$ wget http://ddebs.ubuntu.com/pool/main/l/linux/linux-image-4.8.0-46-generic-dbgsym_4.8.0-46.49_amd64.ddeb
...
Then extract the vmlinux image from the package.

$ ls -l /usr/lib/debug/boot/vmlinux-4.8.0-46-generic
-rw-r--r-- 1 root root 509M Mar 31 12:43
/usr/lib/debug/boot/vmlinux-4.8.0-46-generic
$

Run crash for 'live system':

 $ sudo crash /usr/lib/debug/boot/vmlinux-4.8.0-46-generic /proc/kcore
/boot/System.map-4.8.0-46-generic
[sudo] password for kaiwan:

crash 7.1.5
Copyright (C) 2002-2016  Red Hat, Inc.
This GDB was configured as "x86_64-unknown-linux-gnu"...
--snip--

crash: seek error: kernel virtual address: ffffffff81f5dcc0  type: "possible"
WARNING: cannot read cpu_possible_map
crash: seek error: kernel virtual address: ffffffff81f5dc40  type: "present"
WARNING: cannot read cpu_present_map
crash: seek error: kernel virtual address: ffffffff81f5dc80  type: "online"
WARNING: cannot read cpu_online_map
crash: seek error: kernel virtual address: ffffffff81f5dc00  type: "active"
WARNING: cannot read cpu_active_map
crash: seek error: kernel virtual address: ffffffff81e2a070  type: "pv_init_ops"
crash: seek error: kernel virtual address: ffffffff82167130  type:
"shadow_timekeeper xtime_sec"
crash: seek error: kernel virtual address: ffffffff81e0d304  type: "init_uts_ns"
crash: /boot/System.map-4.8.0-46-generic and /proc/kcore do not match!

Usage:

  crash [OPTION]... NAMELIST MEMORY-IMAGE[@ADDRESS] (dumpfile form)
  crash [OPTION]... [NAMELIST]             (live system form)

Enter "crash -h" for details.
$

It _does_ load up with the --minimal switch, but of course I'd like to
run it with full capabilities.


FYI, output with debug ON:

$ sudo crash -d5 /usr/lib/debug/boot/vmlinux-4.8.0-46-generic
/proc/kcore /boot/System.map-4.8.0-46-generic

crash 7.1.5
Copyright (C) 2002-2016  Red Hat, Inc.
--snip--

get_live_memory_source: /proc/kcore
proc_kcore_data:
       flags: 0 (KCORE_LOCAL|KCORE_ELF64)
    segments: 17
  elf_header: 55f59ded06e0
       elf64: 55f59ded06e0
      load64: 55f59ded0758
       elf32: 0
      load32: 0

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 7fffff602000
       p_vaddr: ffffffffff600000
       p_paddr: 0
      p_filesz: 1000
       p_memsz: 1000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 7fff9da02000
       p_vaddr: ffffffff9da00000
       p_paddr: 0
      p_filesz: 1268000
       p_memsz: 1268000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 2922c0002000
       p_vaddr: ffffa922c0000000
       p_paddr: 0
      p_filesz: 1fffffffffff
       p_memsz: 1fffffffffff
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 7fffc0002000
       p_vaddr: ffffffffc0000000
       p_paddr: 0
      p_filesz: 3f000000
       p_memsz: 3f000000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a100003000
       p_vaddr: ffff96a100001000
       p_paddr: 0
      p_filesz: 57000
       p_memsz: 57000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 6a0000002000
       p_vaddr: ffffea0000000000
       p_paddr: 0
      p_filesz: 2000
       p_memsz: 2000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a10005b000
       p_vaddr: ffff96a100059000
       p_paddr: 0
      p_filesz: 33000
       p_memsz: 33000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a100102000
       p_vaddr: ffff96a100100000
       p_paddr: 0
      p_filesz: 77b5f000
       p_memsz: 77b5f000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 6a0000006000
       p_vaddr: ffffea0000004000
       p_paddr: 0
      p_filesz: 1dee000
       p_memsz: 1dee000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a177c63000
       p_vaddr: ffff96a177c61000
       p_paddr: 0
      p_filesz: 2fb000
       p_memsz: 2fb000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a177f5f000
       p_vaddr: ffff96a177f5d000
       p_paddr: 0
      p_filesz: 34af4000
       p_memsz: 34af4000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 6a0001dff000
       p_vaddr: ffffea0001dfd000
       p_paddr: 0
      p_filesz: d2d000
       p_memsz: d2d000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a1aca7e000
       p_vaddr: ffff96a1aca7c000
       p_paddr: 0
      p_filesz: 9903000
       p_memsz: 9903000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a1b8001000
       p_vaddr: ffff96a1b7fff000
       p_paddr: 0
      p_filesz: 1000
       p_memsz: 1000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 6a0002e01000
       p_vaddr: ffffea0002dff000
       p_paddr: 0
      p_filesz: 1000
       p_memsz: 1000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 16a200002000
       p_vaddr: ffff96a200000000
       p_paddr: 0
      p_filesz: 142800000
       p_memsz: 142800000
       p_align: 4096

  Elf64_Phdr:
        p_type: 1
       p_flags: 7
      p_offset: 6a0004002000
       p_vaddr: ffffea0004000000
       p_paddr: 0
      p_filesz: 50a0000
       p_memsz: 50a0000
       p_align: 4096

readmem: read_proc_kcore() -> /proc/kcore
crash: pv_init_ops exists: ARCH_PVOPS
_text: ffffffff81000000  Kernel code: 1aaa00000 -> phys_base: 1a9a00000

gdb /usr/lib/debug/boot/vmlinux-4.8.0-46-generic
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 "x86_64-unknown-linux-gnu"...

<readmem: ffffffff81f5dcc0, KVADDR, "possible", 64, (ROE), 55f59c515060>
<read_proc_kcore: addr: ffffffff81f5dcc0 paddr: 1ab95dcc0 cnt: 64>
crash: seek error: kernel virtual address: ffffffff81f5dcc0  type: "possible"
WARNING: cannot read cpu_possible_map
<readmem: ffffffff81f5dc40, KVADDR, "present", 64, (ROE), 55f59c515060>
<read_proc_kcore: addr: ffffffff81f5dc40 paddr: 1ab95dc40 cnt: 64>
crash: seek error: kernel virtual address: ffffffff81f5dc40  type: "present"
WARNING: cannot read cpu_present_map
<readmem: ffffffff81f5dc80, KVADDR, "online", 64, (ROE), 55f59c515060>
<read_proc_kcore: addr: ffffffff81f5dc80 paddr: 1ab95dc80 cnt: 64>
crash: seek error: kernel virtual address: ffffffff81f5dc80  type: "online"
WARNING: cannot read cpu_online_map
<readmem: ffffffff81f5dc00, KVADDR, "active", 64, (ROE), 55f59c515060>
<read_proc_kcore: addr: ffffffff81f5dc00 paddr: 1ab95dc00 cnt: 64>
crash: seek error: kernel virtual address: ffffffff81f5dc00  type: "active"
WARNING: cannot read cpu_active_map
<readmem: ffffffff81e2a070, KVADDR, "pv_init_ops", 8, (ROE), 7fff3eafb4b0>
<read_proc_kcore: addr: ffffffff81e2a070 paddr: 1ab82a070 cnt: 8>
crash: seek error: kernel virtual address: ffffffff81e2a070  type: "pv_init_ops"
<readmem: ffffffff82167130, KVADDR, "shadow_timekeeper xtime_sec", 8,
(ROE), 7fff3eafb460>
<read_proc_kcore: addr: ffffffff82167130 paddr: 1abb67130 cnt: 8>
crash: seek error: kernel virtual address: ffffffff82167130  type:
"shadow_timekeeper xtime_sec"
xtime timespec.tv_sec: 8: Thu Jan  1 05:30:08 1970
<readmem: ffffffff81e0d304, KVADDR, "init_uts_ns", 390, (ROE), 55f59c2b9e3c>
<read_proc_kcore: addr: ffffffff81e0d304 paddr: 1ab80d304 cnt: 390>
crash: seek error: kernel virtual address: ffffffff81e0d304  type: "init_uts_ns"
utsname:
     sysname:
    nodename:
     release:
     version:
     machine:
  domainname:
base kernel version: 0.0.0
<readmem: ffffffff81a000c0, KVADDR, "accessible check", 8, (ROE|Q),
7fff3eaf87b0>
<read_proc_kcore: addr: ffffffff81a000c0 paddr: 1ab4000c0 cnt: 8>
crash: seek error: kernel virtual address: ffffffff81a000c0  type:
"accessible check"
crash: /boot/System.map-4.8.0-46-generic and /proc/kcore do not match!

Usage:

  crash [OPTION]... NAMELIST MEMORY-IMAGE[@ADDRESS] (dumpfile form)
  crash [OPTION]... [NAMELIST]             (live system form)

Enter "crash -h" for details.
$

The similar procedure worked just fine on [L]Ubuntu 15.10.
Any help in solving this would be appreciated, TIA!

-Kaiwan.

Thanks & Regards,
Kaiwan.




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