Re: [perf] perf_event_open() sometimes returning 0

[Vince Weaver]

On Thu, 2 Jan 2020, Vince Weaver wrote:

> so I was tracking down some odd behavior in the perf_fuzzer which turns 
> out to be because perf_even_open() sometimes returns 0 (indicating a file 
> descriptor of 0) even though as far as I can tell stdin is still open.

error is triggered if aux_sample_size has non-zero value.

seems to be this line in kernel/events/core.c:


 if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader))
                goto err_locked;


(note, err is never set)


Vince