[Crash-utility] problems running crash on recent rawhide live kernels

[Hariharan S Reddy]

Hi Dave,

I also came across the same problem,

tt->refresh_hash_table is set to refresh_hlist_task_table_v2(),

after executing the function the tt->current is set to 0 (zero).

(gdb) p *tt
$3 = {current = 0x0, context_array = 0x8194e4f0, refresh_task_table =
0x800b1380 <refresh_hlist_task_table_v2>, flags = 1608, task_start = 0,
task_end = 0, task_local = 0x8179bda0,
  max_tasks = 154, nr_threads = 70, running_tasks = 2, retries = 0,
panicmsg = 0, panic_processor = 0, idle_threads = {3384520, 12953368, 0
<repeats 62 times>}, panic_threads = {
    0 <repeats 64 times>}, panic_ksp = {0 <repeats 64 times>}, active_set =
{3384520, 32872136, 0 <repeats 62 times>}, hardirq_ctx = {0 <repeats 64
times>}, hardirq_tasks = {
    0 <repeats 64 times>}, softirq_ctx = {0 <repeats 64 times>},
softirq_tasks = {0 <repeats 64 times>}, panic_task = 0, this_task = 0,
pidhash_len = 1024, pidhash_addr = 4037248,
  last_task_read = 12953368, last_thread_info_read = 13058048, last_mm_read
= 0, task_struct = 0x815eb8e0 "", thread_info = 0x81623ad0 "", mm_struct =
0x8175e420 ""}
(gdb)

Regards
                                                                            
 Hariharan T.S.                                                             
 System Software Engineer,                                                  
 zSeries - Red Hat Enterprise Linux,                                        
 India Software Lab - IBM Systems & Technology Group,                       
 Embassy Golf Links Business Park, Bangalore, INDIA                         
 Direct +91-80-4177-7545                                                    
 e-mail: hariharan.ts at in.ibm.com                                            
 India Software Lab                                                         
                                                                            





Jeff Layton wrote:
      I was trying to run crash against a live rawhide kernel and am
      getting
      some errors when I try to start it:       crash: invalid task address
      in pid_hash: ccccccccccccca84      crash: invalid task address in
      pid_hash: ccccccccccccca84      ...      crash: invalid task address in
      pid_hash: ccccccccccccca84       crash: cannot gather a stable task
      list via pid_hash (500 retries)

      ...and then crash exits. There are a few messages in dmesg:       crash
      memory driver: version 1.0      crash memory driver: !page_is_ram(pfn:
      61000000c)

      Relevant packages:       kernel-2.6.24-0.62.rc3.git5.fc9.x86_64  
      kernel-debuginfo-2.6.24-0.62.rc3.git5.fc9.x86_64  
      crash-4.0-4.10.x86_64

      ... the host is a FV xen guest (but that shouldn't matter, should
      it?).

      I'm hoping I'm just doing something wrong, but I don't see anything
      right offhand.


Hard to do anything wrong, i.e., you just have to enter "crash".

With a kernel that new, it certainly could be shifting sands syndrome.

It did get quite a long way before failing.  I wonder if something's
changed upstream associated with the pid_hash code?  Can you verify
that the tt->refresh_hash_table gets set to refresh_hlist_task_table_v2()?

If the system is accessible to me (reply offline), I'll be happy to
take a look.

Dave

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