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bpf: Fail PERF_EVENT_IOC_SET_BPF when bpf_get_[stack|stackid] cannot work

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bpf_get_[stack|stackid] on perf_events with precise_ip uses callchain
attached to perf_sample_data. If this callchain is not presented, do not
allow attaching BPF program that calls bpf_get_[stack|stackid] to this
event.

In the error case, -EPROTO is returned so that libbpf can identify this
error and print proper hint message.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723180648.1429892-3-songliubraving@fb.com
This commit is contained in:
Song Liu
2020-07-23 11:06:45 -07:00
committed by Alexei Starovoitov
parent 7b04d6d60f
commit 5d99cb2c86
3 changed files with 23 additions and 1 deletions
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3
kernel/bpf/verifier.c
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@@ -4962,6 +4962,9 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
env->prog->has_callchain_buf = true;
}
if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
env->prog->call_get_stack = true;
if (changes_data)
clear_all_pkt_pointers(env);
return 0;