Re: [Crash-utility] timer: invalid list entry: 1

wfi (is wait for interrupt), in the sense we let the cpu go ino idle/dormant when he has nothing to do. and the thread who has been scheduled earliest, the timer would have set accordingly and then wake the cpu up. here we are missing both timer interrupt on both cpu. that means that timer counter has much gone ahead, and it will never match programmed compare values. so its system freeze, as interrupts are not happening. in that freeze, we have special keryboard interrupt to take task dump and other dumps. on that ramdump which I have crash utility would show crash> bt -a PID: 0      TASK: c097b8b0  CPU: 0   COMMAND: "swapper/0" bt: WARNING: cannot get stackframe for task PID: 0      TASK: dc84ca40  CPU: 1   COMMAND: "swapper/1" bt: WARNING: cannot get stackframe for task and timer crash> timer TVEC_BASES[0]: c0a419c0 JIFFIES 4297762 EXPIRES  TIMER_LIST  FUNCTION     128   c1621ea8   c007260c  <idle_worker_timeout>   30208   c0b81f04   c04e4244  <inet_frag_secret_rebuild>   30720   c0b7f264   c0461440  <flow_cache_new_hashrnd>   30840   dba2be04   c0068ebc  <process_timeout>   38228   dbae5e04   c0068ebc  <process_timeout> 11796480   c097cb64   c0010aa4  <sched_clock_poll> 4294937694   c0a6f118   c026f820  <rx_timeout_handler> 4294945658   c16238fc   c007412c  <delayed_work_timer_fn> 4294945667   d811be14   c0068ebc  <process_timeout> 4294945700   c16237cc   c007412c  <delayed_work_timer_fn> 4294945700   c16236e0   c007412c  <delayed_work_timer_fn> 4294946020   c0a1dcbc   c007412c  <delayed_work_timer_fn> 4294946029   dca8f884   c007412c  <delayed_work_timer_fn> 4294946504   c0b871c4   c007412c  <delayed_work_timer_fn> 4294950720   c0b81d6c   c007412c  <delayed_work_timer_fn> timer: invalid list entry: 1 timer: ignoring faulty timer list at index 44 of timer array timer: invalid list entry: 1 timer: ignoring faulty timer list at index 44 of timer array TVEC_BASES[1]: dc85e000 JIFFIES 4297762 EXPIRES  TIMER_LIST  FUNCTION     384   c0a42ba8   c007260c  <idle_worker_timeout> 4297862   dbec0dfc   c007412c  <delayed_work_timer_fn> 4297897   c162c6e0   c007412c  <delayed_work_timer_fn> 4297962   dbec0ea0   c04a7cec  <estimation_timer> 4297997   c162c7cc   c007412c  <delayed_work_timer_fn> 4300768   dcb36654   c007412c  <delayed_work_timer_fn> 4309824   c0a20024   c0516718  <addrconf_verify> 4327762   dcaabf54   c0068ebc  <process_timeout> 4327808   c162aea8   c007260c  <idle_worker_timeout> 4357762   dbaa3e04   c0068ebc  <process_timeout> 4357762   dbaa3e04   c0068ebc  <process_timeout> 4357888   c0b83fa4   c04e4244  <inet_frag_secret_rebuild> 4357888   c0b84694   c04e4244  <inet_frag_secret_rebuild> 4357888   c0b83fa4   c04e4244  <inet_frag_secret_rebuild> 4357888   c0b84694   c04e4244  <inet_frag_secret_rebuild> Regards, Oza. ________________________________ From: Dave Anderson <anderson(a)redhat.com&gt; To: paawan oza <paawan1982(a)yahoo.com&gt; Cc: "Discussion list for crash utility usage, maintenance and development" <crash-utility(a)redhat.com&gt; Sent: Friday, 1 March 2013 10:49 PM Subject: Re: [Crash-utility] timer: invalid list entry: 1 ----- Original Message ----- I don't know much about the ARM architecture, and the only sample SMP ARM dumpfile I have on hand shows the non-panicking cpu blocked in default_idle().  So I don't understand how "wfi" would come into play. What does "bt -a" show? Right, I understand where the error message came from. The crash utility's do_list() function is simply reporting what it sees in the list_head-type linked list that it was following. I have only seen these types of timer command errors in vmcores that were generated with the "snap.so" extension module, or when running the command on a live system.  And both of those scenarios make perfect sense because the underlying kernel was running/modifying the timer-related data structures while the memory was being copied. Presuming that the crash was taken with kdump, you would typically expect that the timer data structures would be stable. Dave