so there's a much more serious objtool bug that I found today, apparently it can 
get into an infinite loop with certain randconfigs:

   PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND                                                                                                          
104261 mingo     39  19    8672    936    840 R 100.0  0.0 115:03.97 objtool                                                                                                          
104485 mingo     39  19    8672    876    780 R 100.0  0.0 115:03.71 objtool                                                                                                          
115277 mingo     39  19    8808    892    796 R 100.0  0.0 114:59.38 objtool                  

unfortunately 'perf record -g' does not seem to be able to resolve it:

fomalhaut:~> perf record -g -p 104261 -a sleep 1
Warning:
PID/TID switch overriding SYSTEM[ perf record: Woken up 17 times to write data ]
[ perf record: Captured and wrote 4.076 MB perf.data (4015 samples) ]

Samples: 4K of event 'cycles:ppp', Event count (approx.): 3342262267                                                                                                                  
  Children      Self  Command  Shared Object      Symbol                                                                                                                              
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184bf00
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184bf70
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184bfe0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c050
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c0c0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c130
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c1a0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c210
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c280
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c2f0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c360
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c3d0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c440
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c4b0
+  100.00%     0.00%  objtool  [unknown]          [k] 0x000000000184c520

Plain 'perf top' shows:

Overhead  Shared Object       Symbol                                                                                                                                                  
  95.36%  objtool             [.] validate_branch
   2.36%  objtool             [.] find_symbol_by_offset
   0.50%  libc-2.22.so        [.] __strcmp_sse2_unaligned
   0.47%  [kernel]            [k] nmi
   0.06%  [kernel]            [k] format_decode
   0.05%  objtool             [.] strcmp@plt

I've attached the config that triggers it.

Thanks,

	Ingo