Re: FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))

From: Vince Weaver
Date: Wed Aug 28 2013 - 12:49:16 EST


On Wed, 28 Aug 2013, Dave Jones wrote:
> Quite often just rerunning that last syscall that caused the oops/warn
> isn't sufficient to trigger an issue. (Though it may be for this specific
> bug that may not be the case..)
>
> Vince has a variant of trinity focussed just on perf which also has some
> neat replay/bisecting capabilities to narrow down test cases.
> I think I might need to add something like that at some point.

Yes, you can get the perf_fuzzer code here:
git clone https://github.com/deater/perf_event_tests.git
in the fuzzer directory

Bisecting down which perf_event_open() call causes problems is still very
labor intensive even with the other tools I've added to help. Even if the
bug is triggered right away (within the first 100,000 calls or so) it can
take hours to narrow things down to the two or three syscalls needed to
reproduce the problem. Especially if you need to reboot after triggering
the issue.

Vince
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/