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