Re: [PATCH] bpf: Put perf_events check ahead of bpf prog

From: Alexei Starovoitov
Date: Sat Jun 27 2015 - 03:55:33 EST


On 6/26/15 11:44 PM, He Kuang wrote:
@@ -1141,13 +1141,13 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
int size, __size, dsize;
int rctx;

- if (prog && !trace_call_bpf(prog, regs))
- return;
-
head = this_cpu_ptr(call->perf_events);
if (hlist_empty(head))
return;

+ if (prog && !trace_call_bpf(prog, regs))
+ return;

I considered doing that before placing it where it is now.
There were some issues with this approach. Trying to remember.
I'm traveling at the moment. Will elaborate next week.
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