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Commit c8c088ba authored by Yonghong Song's avatar Yonghong Song Committed by Daniel Borkmann
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bpf: set maximum number of attached progs to 64 for a single perf tp



cgropu+bpf prog array has a maximum number of 64 programs.
Let us apply the same limit here.

Fixes: e87c6bc3 ("bpf: permit multiple bpf attachments for a single perf event")
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 2b279419
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+2 −1
Original line number Diff line number Diff line
@@ -1447,6 +1447,7 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)
	rcu_read_lock();
	prog = rcu_dereference(progs)->progs;
	for (; *prog; prog++)
		if (*prog != &dummy_bpf_prog.prog)
			cnt++;
	rcu_read_unlock();
	return cnt;
+8 −0
Original line number Diff line number Diff line
@@ -759,6 +759,8 @@ const struct bpf_prog_ops perf_event_prog_ops = {

static DEFINE_MUTEX(bpf_event_mutex);

#define BPF_TRACE_MAX_PROGS 64

int perf_event_attach_bpf_prog(struct perf_event *event,
			       struct bpf_prog *prog)
{
@@ -772,6 +774,12 @@ int perf_event_attach_bpf_prog(struct perf_event *event,
		goto unlock;

	old_array = event->tp_event->prog_array;
	if (old_array &&
	    bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) {
		ret = -E2BIG;
		goto unlock;
	}

	ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
	if (ret < 0)
		goto unlock;