diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2020-01-06 12:03:39 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-23 08:22:33 +0100 |
| commit | 9d7f2619b02327b1c9f7b574603a993e9a07be66 (patch) | |
| tree | fbf50a05c35848c94efd9cf4bd7e6bb5693c7baa /kernel/events | |
| parent | a0edabb91e6e4ca1674a6dd7a8bff9e6cc63cdf5 (diff) | |
perf: Correctly handle failed perf_get_aux_event()
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>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/core.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 8f66a4833ded..6c829e22bad3 100644 --- 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(), |