perf report warnings on tracepoint events hidden by ui

[David Carrillo-Cisneros]

When processing tracepoint events, perf report outputs warnings about
field not founds. The warnings are usually hidden by perf report UI
and appear when using the --stdio option. e.g.

  $ perf record -e syscalls:sys_enter_mmap some_load

  $ perf report --stdio

  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field addr not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field len not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field prot not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field flags not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field fd not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field off not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field addr not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field len not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field prot not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field flags not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field fd not found
  Warning: [syscalls:sys_enter_mmap] eval_num_arg: field off not found

I bisected the warnings to:
  commit d49dadea78624 ("perf tools: Make 'trace' or 'trace_fields'
sort key default for tracepoint events").

that introduced sorting by trace. The event's format in my example is:

  $ cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_socket/format

  name: sys_enter_socket
  ID: 1850
  format:
          field:unsigned short common_type;       offset:0;
size:2; signed:0;
          field:unsigned char common_flags;       offset:2;
size:1; signed:0;
          field:unsigned char common_preempt_count;       offset:3;
   size:1; signed:0;
          field:int common_pid;   offset:4;       size:4; signed:1;

  print fmt: "family: 0x%08lx, type: 0x%08lx, protocol: 0x%08lx",
((unsigned long)(REC->family)), ((unsigned long)(REC->type)),
((unsigned long)(REC->protocol))


An appears to be correctly parsed by event_read_print in
tools/lib/tracevent/event-parse.c . Has anyone seen this before?

Thanks,
David