Re: [PATCH bpf-next] selftests/bpf: Expect at least one kprobe miss in missed/perf_kprobe

[Alexei Starovoitov]

On Thu, Oct 08, 2026 at 06:49 PM Qiliang Yuan <odys.yuan@xxxxxxxxx> wrote:
> bpf_kfunc_common_test is a kfunc of bpf_testmod that other tests call
> as well. When one of them calls it from another kprobe while test2 is
> attached, the kprobe of test2 counts an extra miss, and the test reads
> 2 instead of 1.

Which test is that?
The only other test that calls bpf_kfunc_common_test() is wq.
wq_callback() runs from a workqueue, not from a kprobe,
and serial_test_wq() doesn't run in parallel with anything.
The extra miss comes from test1 in missed_kprobe.c.
It's a kprobe on bpf_fentry_test1() without pid filter.
fentry_test, fexit_test, kprobe_multi_test and many others are not serial.
Their bpf_prog_test_run() calls bpf_fentry_test1(). That runs test1,
it calls bpf_kfunc_common_test() and the kprobe of test2 counts a miss.
Pls fix the commit log and include the output of the failed run.

> -	ASSERT_EQ(info.perf_event.kprobe.missed, 1, "info.perf_event.kprobe.missed");
> +	ASSERT_GE(info.perf_event.kprobe.missed, 1, "info.perf_event.kprobe.missed");

Yesterday you sent the same change for tp_recursion in the same file:
https://lore.kernel.org/bpf/20261008-selftests-bpf-missed-tp-recursion-v1-1-0dd60471d655@xxxxxxxxx/
The cause is the same. test1 there is a kprobe on bpf_fentry_test1() too.
No other kprobe prog with bpf_printk() is involved.
test6 in test_missed_kprobe_recursion() is still ASSERT_EQ 1
and another test bumps it the same way.
Fix all three in one patch.

Also pls send selftest fixes as a series instead of 10 separate mails.

pw-bot: cr