On Mon, Nov 08, 2021 at 06:04:52PM -0500, Steven Rostedt wrote: > On Mon, 8 Nov 2021 15:00:34 -0800 > Beau Belgrave <beaub@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > - memcpy(entry + 1, data, datalen); > > > > + if (unlikely(!copy_nofault(entry + 1, i->count, i))) > > > > > > Need: > > > __trace_event_discard_commit(event_buffer.buffer, event_buffer.event); > > > > > > Because the trace_event_buffer_reserve() will not only allocate space on > > > the ring buffer, but may also disable preemption. > > > > > > -- Steve > > > > > > > Ah, thank you! > > Which reminds me that trace_event_buffer_reserve() expects to be called > with preemption disabled. And I'm guessing that may not be the case for you. > Thanks, should be good there: I have rcu_read_lock_sched() held, which will have preemption disabled during the various probe calls. > I'll change this so that it always disables preemption even if it uses the > filter buffer, and *always* disables preemption on return. > > -- Steve Thanks, -Beau
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