Fix for "bt" command unnecessarily printing an exception frame

Kernel commit 7d65f4a65532 ("irq: Consolidate do_softirq() arch overriden
implementations") renamed the call_softirq to do_softirq_own_stack, and
there is no exception frame also when coming from do_softirq_own_stack.
Without the patch, crash may unnecessarily output an exception frame with
a warning as below:

  crash> foreach bt
  ...
  PID: 0        TASK: ffff914f820a8000  CPU: 25   COMMAND: "swapper/25"
   #0 [fffffe0000504e48] crash_nmi_callback at ffffffffa665d763
   #1 [fffffe0000504e50] nmi_handle at ffffffffa662a423
   #2 [fffffe0000504ea8] default_do_nmi at ffffffffa6fe7dc9
   #3 [fffffe0000504ec8] do_nmi at ffffffffa662a97f
   #4 [fffffe0000504ef0] end_repeat_nmi at ffffffffa70015e8
      [exception RIP: clone_endio+172]
      RIP: ffffffffc005c1ec  RSP: ffffa1d403d08e98  RFLAGS: 00000246
      RAX: 0000000000000000  RBX: ffff915326fba230  RCX: 0000000000000018
      RDX: ffffffffc0075400  RSI: 0000000000000000  RDI: ffff915326fba230
      RBP: ffff915326fba1c0   R8: 0000000000001000   R9: ffff915308d6d2a0
      R10: 000000a97dfe5e10  R11: ffffa1d40038fe98  R12: ffff915302babc40
      R13: ffff914f94360000  R14: 0000000000000000  R15: 0000000000000000
      ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
  --- <NMI exception stack> ---
   #5 [ffffa1d403d08e98] clone_endio at ffffffffc005c1ec [dm_mod]
   #6 [ffffa1d403d08ed0] blk_update_request at ffffffffa6a96954
   #7 [ffffa1d403d08f10] scsi_end_request at ffffffffa6c9b968
   #8 [ffffa1d403d08f48] scsi_io_completion at ffffffffa6c9bb3e
   #9 [ffffa1d403d08f90] blk_complete_reqs at ffffffffa6aa0e95
   #10 [ffffa1d403d08fa0] __softirqentry_text_start at ffffffffa72000dc
   #11 [ffffa1d403d08ff0] do_softirq_own_stack at ffffffffa7000f9a
  --- <IRQ stack> ---
   #12 [ffffa1d40038fe70] do_softirq_own_stack at ffffffffa7000f9a
      [exception RIP: unknown or invalid address]
      RIP: 0000000000000000  RSP: 0000000000000000  RFLAGS: 00000000
      RAX: ffffffffa672eae5  RBX: ffffffffa83b34e0  RCX: ffffffffa672eb12
      RDX: 0000000000000010  RSI: 8b7d6c8869010c00  RDI: 0000000000000085
      RBP: 0000000000000286   R8: ffff914f820a8000   R9: ffffffffa67a94e0
      R10: 0000000000000286  R11: ffffffffa66fb4c5  R12: ffffffffa67a898b
      R13: 0000000000000000  R14: fffffffffffffff8  R15: ffffffffa67a1e68
      ORIG_RAX: 0000000000000000  CS: 0000  SS: ffffffffa672edff
   bt: WARNING: possibly bogus exception frame
   #13 [ffffa1d40038ff30] start_secondary at ffffffffa665fa2c
   #14 [ffffa1d40038ff50] secondary_startup_64_no_verify at ffffffffa6600116
   ...

Reported-by: Marco Patalano <mpatalan@redhat.com>
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>

x86_64.c

@@ -3825,10 +3825,11 @@ x86_64_low_budget_back_trace_cmd(struct bt_info *bt_in)
 		up -= 1;
                 bt->instptr = *up;
 		/*
-		 *  No exception frame when coming from call_softirq.
+		 *  No exception frame when coming from do_softirq_own_stack
+		 *  or call_softirq.
 		 */
 		if ((sp = value_search(bt->instptr, &offset)) && 
-		    STREQ(sp->name, "call_softirq"))
+		    (STREQ(sp->name, "do_softirq_own_stack") || STREQ(sp->name, "call_softirq")))
 			irq_eframe = 0;
                 bt->frameptr = 0;
                 done = FALSE;