[Crash-utility] cannot find stack info on ppc64le

[Han Pingtian]

Hello,

I just noticed that on ppc64le, sometimes "bt" cannot find the stack
info of current process. For example, there is a vmcore captured by
kdump on a ppc64le system, which running with a kernel version 3.10. The
vmcore was captured when kernel oopsed. There is no stack info found by
bt:

crash 7.0.9-2.ael7b
Copyright (C) 2002-2014  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 "powerpc64le-unknown-linux-gnu"...

      KERNEL: /usr/lib/debug/lib/modules/3.10.0-221.ael7b.ppc64le/vmlinux
    DUMPFILE: /var/crash/127.0.0.1-2015.01.15-22:19:14/vmcore  [PARTIAL DUMP]
        CPUS: 16
        DATE: Thu Jan 15 21:18:16 2015
      UPTIME: 17:53:43
LOAD AVERAGE: 213.58, 213.23, 212.70
       TASKS: 1383
    NODENAME: thymelp2.isst.aus.stglabs.ibm.com
     RELEASE: 3.10.0-221.ael7b.ppc64le
     VERSION: #1 SMP Wed Jan 7 09:27:09 EST 2015
     MACHINE: ppc64le  (3425 Mhz)
      MEMORY: 15 GB
       PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log for details)
         PID: 1970
     COMMAND: "cat"
        TASK: c0000003130874a0  [THREAD_INFO: c00000005069c000]
         CPU: 5
       STATE: TASK_RUNNING (PANIC)

crash> set debug 99
debug: 99
crash> bt
PID: 1970   TASK: c0000003130874a0  CPU: 5   COMMAND: "cat"
GETBUF(16384 -> 0)
<readmem: c00000005069c000, KVADDR, "stack contents", 16384, (ROE), 10a81570>
<read_diskdump: addr: c00000005069c000 paddr: 5069c000 cnt: 16384>
read_diskdump: paddr/pfn: 5069c000/5069 -> cache physical page: 50690000
c00000005069c018: do_no_restart_syscall
c00000005069e870: blk_throtl_bio+240
c00000005069e990: clone_endio
c00000005069ea00: generic_make_request_checks+836
c00000005069eab8: hardware_interrupt_common+128
c00000005069eac0: generic_make_request+36
c00000005069eb10: mempool_alloc_slab+36
c00000005069eb30: mempool_alloc+256
c00000005069eb50: mempool_alloc_slab+36
c00000005069ebc0: get_request+948
c00000005069ec00: __split_and_process_bio+1408
c00000005069ec20: autoremove_wake_function
c00000005069ec80: find_busiest_group+544
c00000005069edf0: load_balance+684
c00000005069ee10: blk_throtl_bio+240
c00000005069ee70: find_busiest_group+544
c00000005069eee0: dequeue_task_fair+968
c00000005069ef30: clone_endio
c00000005069ef50: get_page_from_freelist+1436
c00000005069f0a0: pSeries_cause_ipi_mux+112
c00000005069f0c0: smp_send_reschedule+164
c00000005069f0e0: default_wake_function+708
c00000005069f160: __wake_up_locked+116
c00000005069f1b0: ep_poll_callback+444
c00000005069f250: run_posix_cpu_timers+104
c00000005069f2c0: hvterm_raw_put_chars+64
c00000005069f2e0: hvc_console_print+336
c00000005069f3a8: initial_stab+2048
c00000005069f3b0: crash_save_cpu+252
c00000005069f488: cik_cp_resume+13476
c00000005069f490: dev_get_drvdata
c00000005069f580: default_machine_kexec+332
c00000005069f610: pSeries_machine_kexec+60
c00000005069f680: machine_kexec+56
c00000005069f6a0: crash_kexec+312
c00000005069f6f0: dev_attr_show+64
c00000005069f748: cik_cp_resume+13476
c00000005069f750: dev_get_drvdata
c00000005069f7f0: radeon_hwmon_show_temp+72
c00000005069f800: slb_miss_realmode+80
c00000005069f808: dev_get_drvdata
c00000005069f810: radeon_hwmon_show_temp+32
c00000005069f890: die+840
c00000005069f930: bad_page_fault+224
c00000005069f948: radeon_hwmon_show_temp+72
c00000005069f9a0: handle_page_fault+44
c00000005069fa00: dev_attr_show+64
c00000005069fa58: cik_cp_resume+13476
c00000005069fa60: dev_get_drvdata
c00000005069fb00: radeon_hwmon_show_temp+72
c00000005069fb10: slb_miss_realmode+80
c00000005069fb18: dev_get_drvdata
c00000005069fb20: radeon_hwmon_show_temp+32
c00000005069fb60: handle_mm_fault+1724
c00000005069fb80: sysfs_open_file
c00000005069fbd0: handle_page_fault+16
c00000005069fc90: alloc_pages_current+416
c00000005069fd00: dev_attr_show+64
c00000005069fd30: sysfs_read_file+220
c00000005069fde0: sys_read+304
c00000005069fe40: syscall_exit
[3fffd0d6fe88] back_trace:
        task: c0000003130874a0
       flags: 0
     instptr: 0
      stkptr: 0
        bptr: 0
   stackbase: c00000005069c000
    stacktop: c0000000506a0000
          tc: 1003c7b9fa8 (1970, c0000003130874a0)
          hp: 0
         ref: 0
    stackbuf: 10a81570
    textlist: 0
    frameptr: 0
 call_target: none
   eframe_ip: 0
       debug: 0
       radix: 0
     cpumask: 0
 => PC: 0 () FP: 0
  GETBUF(248 -> 1)
    GETBUF(1500 -> 2)
cannot find the stack info.
    FREEBUF(2)
  FREEBUF(1)
crash>


Is this a problem?

Thanks in advance!