On Mon, Nov 16, 2020 at 01:02:09PM -0800, Martin KaFai Lau wrote: > On Mon, Nov 16, 2020 at 07:37:52PM +0100, Florian Lehner wrote: > > bpf handlers for perf events other than tracepoints, kprobes or uprobes > > are attached to the overflow_handler of the perf event. > > > > Perf events of type software/dummy are placeholder events. So when > > attaching a bpf handle to an overflow_handler of such an event, the bpf > > handler will not be triggered. > > > > This fix returns the error EOPNOTSUPP to indicate that attaching a bpf > > handler to a perf event of type software/dummy is not supported. > > > > Signed-off-by: Florian Lehner <dev@xxxxxxxxxxx> > It is missing a Fixes tag. I don't think it actually fixes anything. worse it could break things. Atatching a bpf filter to a dummy event is pointless, but harmless. We allow it now, disallowing it will break whatever programs out there are doing harmless silly things. I really don't see the point of this patch. It grows the kernel code for absolutely no distinguishable benefit.
