On Tue, Jul 25, 2017 at 01:55:12PM +0200, Peter Zijlstra wrote: SNIP > > diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c > index 1b2be63c8528..c98a12f3592c 100644 > --- a/kernel/events/callchain.c > +++ b/kernel/events/callchain.c > @@ -12,6 +12,7 @@ > #include <linux/perf_event.h> > #include <linux/slab.h> > #include <linux/sched/task_stack.h> > +#include <linux/task_work.h> > > #include "internal.h" > > @@ -178,19 +179,94 @@ put_callchain_entry(int rctx) > put_recursion_context(this_cpu_ptr(callchain_recursion), rctx); > } > > +static struct perf_callchain_entry __empty = { .nr = 0, }; > + > +static void perf_callchain_work(struct callback_head *work) > +{ > + struct perf_event *event = container_of(work, struct perf_event, pending_callchain); > + struct perf_output_handle handle; > + struct perf_sample_data sample; > + size_t size; > + int ret; > + > + struct { > + struct perf_event_header header; > + } callchain_event = { > + .header = { > + .type = PERF_RECORD_CALLCHAIN, > + .misc = 0, > + .size = sizeof(callchain_event), > + }, > + }; how about we make this generic for all user space sample_type? I think we could certainly use it for PERF_SAMPLE_STACK_USER, maybe PERF_SAMPLE_REGS_USER would also help.. just a little ;-) I'll check on that jirka -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html