I can think of two places where it can happen:
1) perf_event__synthesize_kernel_mmap
[...]
mmap_name = machine__mmap_name(machine, name_buff, sizeof(name_buff));
if (machine__is_host(machine)) {
...
} else {
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
if (machine__is_default_guest(machine))
filename = (char *) symbol_conf.default_guest_kallsyms;
else {
sprintf(path, "%s/proc/kallsyms", machine->root_dir);
filename = path;
}
}
[...]
event->mmap.header.type = PERF_RECORD_MMAP;
[...]
event->mmap.pid = machine->pid;
2) perf_event__synthesize_modules
[...]
if (machine__is_host(machine))
event->header.misc = PERF_RECORD_MISC_KERNEL;
else
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
[...]
event->mmap.header.type = PERF_RECORD_MMAP;
[...]
event->mmap.pid = machine->pid;
BTW, i am testing this on latest -tip(498c911).
In my case, I am able to recreate this everytime. And have verified that
the event->header.type that I hit here is of type PERF_RECORD_MMAP.