On Thu, 30 Jan 2014 00:32:32 -0500 Dave Jones <da...@redhat.com> wrote:
> On Wed, Jan 29, 2014 at 11:50:43PM -0500, Steven Rostedt wrote: > > Are you running as root? If not, you found another way to get perf to > start function tracing. > > Good point. In this case, I was trying some new experimental trinity code > that starts as root, generates fd's, then drops privs before doing syscalls. > > So the "generate fds" part did some perf_event_open's as root, yeah. > > While that's less scary from a security pov than it was last time, it's still > something that aparently needs fixing. > OK, then I'm not as worried (phew!). But you are correct, this needs to be fixed. How do I run just perf commands from trinity? I do not think this occurs from any other systemcall needing to be run. Peter, Jiri, Although we fixed the bug that let a normal user enable function tracing from perf, we never figured out why perf screws up the function tracing filter accounting. That will happen if you either use a uninitialized ftrace hash, or modify the hash without using the ftrace API. If it is the latter, it is probably done by some kind of use after free. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
