On Mon, Aug 15, 2022 at 5:37 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Mon, Aug 15, 2022 at 11:44:32AM +0200, Jiri Olsa wrote: > > On Mon, Aug 15, 2022 at 10:03:17AM +0200, Peter Zijlstra wrote: > > > On Sat, Aug 13, 2022 at 03:02:52PM -0400, Steven Rostedt wrote: > > > > On Fri, 12 Aug 2022 23:18:15 +0200 > > > > Jiri Olsa <olsajiri@xxxxxxxxx> wrote: > > > > > > > > > the patch below moves the bpf function into sepatate object and switches > > > > > off the -mrecord-mcount for it.. so the function gets profile call > > > > > generated but it's not visible to ftrace > > > > > > Why ?!? > > > > there's bpf dispatcher code that updates bpf_dispatcher_xdp_func > > function with bpf_arch_text_poke and that can race with ftrace update > > if the function is traced > > I thought bpf_arch_text_poke() wasn't allowed to touch kernel code and > ftrace is in full control of it ? ftrace is not in "full control" of nop5 and must not be. Soon we will have nop5 in the middle of the function. ftrace must not touch it.
