[Crash-utility] Crash issues with ARM aarch64 on a live system

Thu May 21 06:18:01 UTC 2020

On Wed, May 20, 2020 at 10:19 PM Siamak Nazari <siamaknazari at yahoo.com> wrote:
>
> Apologies if this the wrong place to ask this question. If in fact this is the wrong alias to post this question, appreciate a pointer in the right direction. We have been trying to get crash working on a live kernel (aarch64) but have not been able to.
>
> Based on the crash help text:
>
> --machdep option=value
>     Pass an option and value pair to machine-dependent code.  These
>     architecture-specific option/pairs should only be required in
>     very rare circumstances:
>
>     ARM64:
>       phys_offset=<physical-address>
>       kimage_voffset=<kimage_voffset-value>
>       max_physmem_bits=<value>
>       vabits_actual=<value>
>
> We probably need to specify the proper values for phys_offset and kimage_voffset. kimage_offset is in /proc/kallsyms, but not phys_offset. It is just not clear where the values should come from. I did try using the value of kimage_offset  found in /proc/kallsyms but that did not help. It is not clear where one needs to get the values from (and in fact a casual reading of the crash source seems to try to compute the values automatically)
>
> Here is some additional information:
>
> # uname -a
> Linux bringup 5.1.0 #1 SMP Fri Oct 11 17:01:55 UTC 2019 aarch64 GNU/Linux
>
> # crash -s
> crash: /proc/kcore: No such file or directory

Seem like your kernel is not configured with CONFIG_PROC_KCORE
(/proc/kcore support).
With /proc/kcore you don't need to supply any additional options &
values to crash.

> WARNING: could not find MAGIC_START!
> WARNING: cannot read linux_banner string
> crash: /boot/vmlinux-5.1.0 and /dev/mem do not match!
>
> This is with additional debugging turned on:
>
> # ./crash --version
>
> crash 7.2.8++
> Copyright (C) 2002-2020  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".
>
> Here is crash running with -d flag:
>
> find_booted_kernel: check: /boot/vmlinux-5.1.0
> find_booted_kernel: found: /boot/vmlinux-5.1.0
> get_live_memory_source: /dev/mem
> /proc/version:
> Linux version 5.1.0 (oe-user at oe-host) (gcc version 7.3.0 (GCC)) #1 SMP Fri Oct 11 17:01:55 UTC 2019
> /boot/vmlinux-5.1.0:
> Linux version 5.1.0 (oe-user at oe-host) (gcc version 7.3.0 (GCC)) #1 SMP Fri Oct 11 17:01:55 UTC 2019
> crash: /proc/kcore: No such file or directory
> readmem: read_dev_mem() -> /dev/mem
> VA_BITS: 48
> kimage_voffset: fffeffff88000000
> phys_offset: 0
> physvirt_offset: 800000000000
> gdb --quiet /boot/vmlinux-5.1.0
> GETBUF(328 -> 0)
>   GETBUF(1500 -> 1)
>   FREEBUF(1)
> FREEBUF(0)
> <readmem: ffff0000109c63b8, KVADDR, "kernel_config_data", 32768, (ROE), aaaad82d4630>
> <read_dev_mem: addr: ffff0000109c63b8 paddr: 889c63b8 cnt: 3144>
> <read_dev_mem: addr: ffff0000109c7000 paddr: 889c7000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109c8000 paddr: 889c8000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109c9000 paddr: 889c9000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109ca000 paddr: 889ca000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109cb000 paddr: 889cb000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109cc000 paddr: 889cc000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109cd000 paddr: 889cd000 cnt: 4096>
> <read_dev_mem: addr: ffff0000109ce000 paddr: 889ce000 cnt: 952>
> <readmem: ffff0000109c63b0, KVADDR, "kernel_config_data MAGIC_START", 8, (ROE), ffffe6a6d5a0>
> <read_dev_mem: addr: ffff0000109c63b0 paddr: 889c63b0 cnt: 8>
> WARNING: could not find MAGIC_START!
> GETBUF(328 -> 0)
> FREEBUF(0)
> GETBUF(8 -> 0)
> <readmem: ffff000010e1c6d8, KVADDR, "possible", 8, (ROE|Q), aaaacd15f258>
> <read_dev_mem: addr: ffff000010e1c6d8 paddr: 88e1c6d8 cnt: 8>
> cpu_possible_mask: cpus: (none)
> <readmem: ffff000010e1c6d0, KVADDR, "present", 8, (ROE|Q), aaaacd15f258>
> <read_dev_mem: addr: ffff000010e1c6d0 paddr: 88e1c6d0 cnt: 8>
>  cpu_present_mask: cpus: (none)
> <readmem: ffff000010e1c6c8, KVADDR, "online", 8, (ROE|Q), aaaacd15f258>
> <read_dev_mem: addr: ffff000010e1c6c8 paddr: 88e1c6c8 cnt: 8>
>   cpu_online_mask: cpus: (none)
> <readmem: ffff000010e1c6e0, KVADDR, "active", 8, (ROE|Q), aaaacd15f258>
> <read_dev_mem: addr: ffff000010e1c6e0 paddr: 88e1c6e0 cnt: 8>
>   cpu_active_mask: cpus: (none)
> FREEBUF(0)
> GETBUF(328 -> 0)
> FREEBUF(0)
> GETBUF(328 -> 0)
> FREEBUF(0)
> GETBUF(328 -> 0)
> FREEBUF(0)
> <readmem: ffff000010ef8150, KVADDR, "shadow_timekeeper xtime_sec", 8, (ROE), ffffe6a650b8>
> <read_dev_mem: addr: ffff000010ef8150 paddr: 88ef8150 cnt: 8>
> xtime timespec.tv_sec: 0: Wed Dec 31 16:00:00 1969
> <readmem: ffff000010e2533c, KVADDR, "init_uts_ns", 390, (ROE), aaaacd0fd194>
> <read_dev_mem: addr: ffff000010e2533c paddr: 88e2533c cnt: 390>
> utsname:
>      sysname:
>     nodename:
>      release:
>      version:
>      machine:
>   domainname:
> base kernel version: 0.0.0
> <readmem: ffff0000109b0098, KVADDR, "accessible check", 8, (ROE|Q), ffffe6a64770>
> <read_dev_mem: addr: ffff0000109b0098 paddr: 889b0098 cnt: 8>
> <readmem: ffff0000109b0098, KVADDR, "read_string characters", 1499, (ROE|Q), ffffe6a64ae8>
> <read_dev_mem: addr: ffff0000109b0098 paddr: 889b0098 cnt: 1499>
> WARNING: cannot read linux_banner string
> /proc/version:
> Linux version 5.1.0 (oe-user at oe-host) (gcc version 7.3.0 (GCC)) #1 SMP Fri Oct 11 17:01:55 UTC 2019
> linux_banner:
>
> crash: /boot/vmlinux-5.1.0 and /dev/mem do not match!
>
>
>
>
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