diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2013-04-13 15:36:49 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2013-04-15 17:39:52 +0200 |
| commit | 515619f209114697fabd21eed1623bfa69746815 (patch) | |
| tree | 84655a5404fb290f8492f3f953f9e61007f7c3e2 /kernel/trace/trace_uprobe.c | |
| parent | 32520b2c695b23221751eb09360a6a3dd3105b52 (diff) | |
uprobes/perf: Avoid perf_trace_buf_prepare/submit if ->perf_events is empty
perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense
if this task/CPU has no active counters. Change uprobe_perf_print()
to return if hlist_empty(call->perf_events).
Note: this is not uprobe-specific, we can change other users too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Diffstat (limited to 'kernel/trace/trace_uprobe.c')
| -rw-r--r-- | kernel/trace/trace_uprobe.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 37ccb72f0f3b..32494fb0ee64 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -820,6 +820,10 @@ static void uprobe_perf_print(struct trace_uprobe *tu, return; preempt_disable(); + head = this_cpu_ptr(call->perf_events); + if (hlist_empty(head)) + goto out; + entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx); if (!entry) goto out; @@ -836,7 +840,6 @@ static void uprobe_perf_print(struct trace_uprobe *tu, for (i = 0; i < tu->nr_args; i++) call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset); - head = this_cpu_ptr(call->perf_events); perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL); out: preempt_enable(); |