Messages in this thread | | | Date | Fri, 12 Jun 2015 21:29:42 -0400 | From | Steven Rostedt <> | Subject | Re: perf,ftrace: fuzzer triggers warning in trace_events_filter code |
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On Fri, 12 Jun 2015 21:15:10 -0400 (EDT) Vince Weaver <vincent.weaver@maine.edu> wrote:
> On Fri, 12 Jun 2015, Steven Rostedt wrote: > > > On Fri, 12 Jun 2015 17:18:22 -0400 (EDT) > > Vince Weaver <vincent.weaver@maine.edu> wrote: > > > > > > > > So I've modified my fuzzer to try to exercise the > > > PERF_EVENT_IOC_SET_FILTER ioctl() and it is starting to turn up some > > > warnings. > > > > Is there any way to know what the filter string you used that generated > > this? > > Various seem to trigger it. One example is > > ext4:ext4_truncate_exit > (((dev<=913)blocks==916)common_type&756) >
Thanks, OK, I know what the issue is. I'm also thinking the solution may simply be removing that WARN_ON(). But I'll look at it a little deeper before deciding that.
The WARN_ON() simply detected an anomaly, but nothing breaks when that anomaly occurs. Well, I don't see anything breaking, it just expected that we couldn't get to this path, but now we know we can. Thus the solution is to remove the WARN_ON() or detect the bad filter before getting there.
-- Steve
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