From: Mark Rutland mark.rutland@arm.com
commit da9ec3d3dd0f1240a48920be063448a2242dbd90 upstream.
Vince reports a worrying issue:
| 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.
... and further the cause:
| 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)
This seems to be a thinko in commit:
ab43762ef010967e ("perf: Allow normal events to output AUX data")
... and we should probably return -EINVAL here, as this should only happen when the new event is mis-configured or does not have a compatible aux_event group leader.
Fixes: ab43762ef010967e ("perf: Allow normal events to output AUX data") Reported-by: Vince Weaver vincent.weaver@maine.edu Signed-off-by: Mark Rutland mark.rutland@arm.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Ingo Molnar mingo@kernel.org Acked-by: Alexander Shishkin alexander.shishkin@linux.intel.com Tested-by: Vince Weaver vincent.weaver@maine.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/events/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11182,8 +11182,10 @@ SYSCALL_DEFINE5(perf_event_open, } }
- if (event->attr.aux_output && !perf_get_aux_event(event, group_leader)) + if (event->attr.aux_output && !perf_get_aux_event(event, group_leader)) { + err = -EINVAL; goto err_locked; + }
/* * Must be under the same ctx::mutex as perf_install_in_context(),