Re: [PATCH v11 11/11] tracing/probes: Add a new testcase for BTF typecasts

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

This has a problem and needs some updates.

On Fri, 26 Jun 2026 23:16:04 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc b/tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc
> new file mode 100644
> index 000000000000..96791e120b7d
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/btf_probe_event.tc
> @@ -0,0 +1,51 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: BTF event with typecast and percpu access
> +# requires: dynamic_events "this_cpu_read(<fetcharg>)":README "[(structname[,field])]<argname>[->field[->field|.field...]]":README
> +
> +# Check if the sample module is loaded
> +if ! lsmod | grep -q trace_events_sample; then
> +  modprobe trace-events-sample || exit_unsupported

I think this should be exit_unresolved.

> +fi
[...]
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/btf_typecast_accepted.tc b/tools/testing/selftests/ftrace/test.d/dynevent/btf_typecast_accepted.tc
> new file mode 100644
> index 000000000000..acf0b5a917d3
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/btf_typecast_accepted.tc
> @@ -0,0 +1,107 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: BTF typecast and percpu access syntax validation
> +# requires: dynamic_events "this_cpu_read(<fetcharg>)":README "[(structname[,field])]<argname>[->field[->field|.field...]]":README
> +
> +KPROBES=
> +FPROBES=
> +
> +if grep -qF "p[:[<group>/][<event>]] <place> [<args>]" README ; then
> +  KPROBES=yes
> +fi
> +if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; then
> +  FPROBES=yes
> +fi
> +
> +if [ -z "$KPROBES" -a -z "$FPROBES" ] ; then
> +  exit_unsupported
> +fi
> +
> +echo 0 > events/enable
> +echo > dynamic_events
> +
> +# Load trace-events-sample module if available to have per-CPU counter structure defined
> +if ! lsmod | grep -q trace_events_sample; then
> +  modprobe trace-events-sample || true

I think this must be tested, and if the module is not found,
the test must return UNRESOLVED error.

> +fi
[...]
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc
> index 0e65e787e426..1d6d1cf94f16 100644
> --- a/tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/eprobes_syntax_errors.tc
> @@ -21,8 +21,17 @@ check_error 'e:foo/^bar.1 syscalls/sys_enter_openat'	# BAD_EVENT_NAME
>  
>  check_error 'e:foo/bar syscalls/sys_enter_openat arg=^$foo'	# BAD_ATTACH_ARG
>  
> +check_error 'e:foo/bar syscalls/sys_enter_openat arg=^COMM'	# NO_EVENT_FIELD
> +if grep -q '\\$current' README; then

Sashiko found a problem here. Indeed. this is wrong. See below:

> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
> index c817158b99db..e12dc967ec76 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/uprobe_syntax_errors.tc
> @@ -28,4 +28,9 @@ if grep -q ".*symstr.*" README; then
>  check_error 'p /bin/sh:10 $stack0:^symstr'	# BAD_TYPE
>  fi
>  
> +# $current is not supported by uprobe
> +if grep -q "\$current.*" README; then

This is correct check.

Let me fix those.

Thanks,

-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>