Re: [PATCH v2 8/9] selftests/ftrace: Add BTF fields access testcases

[Alan Maguire <alan.maguire@oracle.com>]

On 17/07/2023 16:24, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Add test cases for accessing the data structure fields using BTF info.
> This includes the field access from parameters and retval, and accessing
> string information.
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

One suggestion below, but

Reviewed-by: Alan Maguire <alan.maguire@oracle.com>

> ---
> Changes in v2:
>  - Use '$retval' instead of 'retval'.
>  - Add a test that use both '$retval' and '$arg1' for fprobe.
> ---
>  .../ftrace/test.d/dynevent/add_remove_btfarg.tc    |   11 +++++++++++
>  .../ftrace/test.d/dynevent/fprobe_syntax_errors.tc |    4 ++++
>  2 files changed, 15 insertions(+)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
> index b89de1771655..93b94468967b 100644
> --- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc
> @@ -21,6 +21,8 @@ echo 0 > events/enable
>  echo > dynamic_events
>  
>  TP=kfree
> +TP2=kmem_cache_alloc
> +TP3=getname_flags
>  
>  if [ "$FPROBES" ] ; then
>  echo "f:fpevent $TP object" >> dynamic_events
> @@ -33,6 +35,7 @@ echo > dynamic_events
>  
>  echo "f:fpevent $TP "'$arg1' >> dynamic_events
>  grep -q "fpevent.*object=object" dynamic_events
> +
>  echo > dynamic_events
>  
>  echo "f:fpevent $TP "'$arg*' >> dynamic_events
> @@ -45,6 +48,14 @@ fi
>  
>  echo > dynamic_events
>  
> +echo "t:tpevent $TP2 name=s->name:string" >> dynamic_events
> +echo "f:fpevent ${TP3}%return path=\$retval->name:string" >> dynamic_events
> +

could we test a numeric value like kmem_cache_alloc object size?
also if combos of -> and . are allowed, would be good to test one of
those too.

> +grep -q "tpevent.*name=s->name:string" dynamic_events
> +grep -q "fpevent.*path=\$retval->name:string" dynamic_events
> +
> +echo > dynamic_events
> +
>  if [ "$KPROBES" ] ; then
>  echo "p:kpevent $TP object" >> dynamic_events
>  grep -q "kpevent.*object=object" dynamic_events
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> index 72563b2e0812..49758f77c923 100644
> --- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc
> @@ -103,6 +103,10 @@ check_error 'f vfs_read%return ^$arg*'		# NOFENTRY_ARGS
>  check_error 'f vfs_read ^hoge'			# NO_BTFARG
>  check_error 'f kfree ^$arg10'			# NO_BTFARG (exceed the number of parameters)
>  check_error 'f kfree%return ^$retval'		# NO_RETVAL
> +check_error 'f vfs_read%return $retval->^foo'	# NO_PTR_STRCT
> +check_error 'f vfs_read file->^foo'		# NO_BTF_FIELD
> +check_error 'f vfs_read file^-.foo'		# BAD_HYPHEN
> +check_error 'f vfs_read ^file:string'		# BAD_TYPE4STR
>  else
>  check_error 'f vfs_read ^$arg*'			# NOSUP_BTFARG
>  check_error 't kfree ^$arg*'			# NOSUP_BTFARG
> 
>