crash utility help page:  task


NAME
  task - task_struct and thread_info contents

SYNOPSIS
  task [-R member[,member]] [-dx] [pid | taskp] ...

DESCRIPTION
  This command dumps a formatted display of the contents of a task's
  task_struct and thread_info structures.  Multiple task or PID numbers
  may be entered; if no arguments are entered, the task_struct and
  thread_info structures of the current context are displayed.  The -R option,
  which may also be invoked indirectly via "foreach task", pares the output
  down to one or more structure members.
 
        pid  a process PID.
      taskp  a hexadecimal task_struct pointer.
  -R member  a comma-separated list of one or more task_struct and/or
             thread_info structure members.
         -x  override default output format with hexadecimal format.
         -d  override default output format with decimal format.

EXAMPLES
  Dump the task_struct and thread_info structures of the current context
  in hexadecimal format:

    crash> task -x
    PID: 3176   TASK: f2451550  CPU: 1   COMMAND: "memtest"
    struct task_struct {
      state = 0x0, 
      stack = 0xf05b6000, 
      usage = {
        counter = 0x2
      }, 
      flags = 0x402040, 
      ptrace = 0x0, 
      lock_depth = 0xffffffff, 
      prio = 0x78, 
      static_prio = 0x78, 
      normal_prio = 0x78, 
      rt_priority = 0x0, 
    ...
      perf_event_ctxp = {0x0, 0x0}, 
      memcg_batch = {
        do_batch = 0x0, 
        memcg = 0x0, 
        bytes = 0x0, 
        memsw_bytes = 0x0
      }
    }
    
    struct thread_info {
      task = 0xf2451550, 
      exec_domain = 0xc0a60860, 
      flags = 0x88, 
      status = 0x0, 
      cpu = 0x1, 
      preempt_count = 0x4010000, 
      addr_limit = {
        seg = 0xc0000000
      }, 
      restart_block = {
    ...
 
  Display the ngroups and groups task_struct members for PID 2958:

    crash> task -R ngroups,groups 2958
    PID: 2958   TASK: c6718000  CPU: 0   COMMAND: "bash"
      ngroups = 6, 
      groups = {504, 8, 9, 1000, 1007, 1006, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
 
  NOTE: When this command is invoked directly (i.e., not from "foreach"), it
  is not necessary to include the "-R" before the task_struct/thread_info
  member name(s).