Re: [PATCH 4/8] tracing: probe-events: Log errro for exceeding the number of arguments

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

On Wed, 26 Feb 2025 15:19:10 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> Add error message when the number of arguments exceeeds the limitation.
> 

Hmm, this is not a fix patch so this should be handled as enhancement.
I'll drop this from probes/fixes.

Thanks,

> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>  kernel/trace/trace_eprobe.c |    2 ++
>  kernel/trace/trace_fprobe.c |    5 ++++-
>  kernel/trace/trace_kprobe.c |    5 ++++-
>  kernel/trace/trace_probe.h  |    1 +
>  kernel/trace/trace_uprobe.c |    9 +++++++--
>  5 files changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index 82fd637cfc19..af9fa0632b57 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -913,6 +913,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
>  	}
>  
>  	if (argc - 2 > MAX_TRACE_ARGS) {
> +		trace_probe_log_set_index(2);
> +		trace_probe_log_err(0, TOO_MANY_ARGS);
>  		ret = -E2BIG;
>  		goto error;
>  	}
> diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
> index e27305d31fc5..372936163c21 100644
> --- a/kernel/trace/trace_fprobe.c
> +++ b/kernel/trace/trace_fprobe.c
> @@ -1201,8 +1201,11 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  		argc = new_argc;
>  		argv = new_argv;
>  	}
> -	if (argc > MAX_TRACE_ARGS)
> +	if (argc > MAX_TRACE_ARGS) {
> +		trace_probe_log_set_index(2);
> +		trace_probe_log_err(0, TOO_MANY_ARGS);
>  		return -E2BIG;
> +	}
>  
>  	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
>  	if (ret)
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index d8d5f18a141a..8287b175667f 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1007,8 +1007,11 @@ static int trace_kprobe_create_internal(int argc, const char *argv[],
>  		argc = new_argc;
>  		argv = new_argv;
>  	}
> -	if (argc > MAX_TRACE_ARGS)
> +	if (argc > MAX_TRACE_ARGS) {
> +		trace_probe_log_set_index(2);
> +		trace_probe_log_err(0, TOO_MANY_ARGS);
>  		return -E2BIG;
> +	}
>  
>  	ret = traceprobe_expand_dentry_args(argc, argv, &dbuf);
>  	if (ret)
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index c47ca002347a..6075afc8ea67 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -546,6 +546,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
>  	C(BAD_BTF_TID,		"Failed to get BTF type info."),\
>  	C(BAD_TYPE4STR,		"This type does not fit for string."),\
>  	C(NEED_STRING_TYPE,	"$comm and immediate-string only accepts string type"),\
> +	C(TOO_MANY_ARGS,	"Too many arguments are specified"),	\
>  	C(TOO_MANY_EARGS,	"Too many entry arguments specified"),
>  
>  #undef C
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index ccc762fbb69c..3386439ec9f6 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -562,8 +562,14 @@ static int __trace_uprobe_create(int argc, const char **argv)
>  
>  	if (argc < 2)
>  		return -ECANCELED;
> -	if (argc - 2 > MAX_TRACE_ARGS)
> +
> +	trace_probe_log_init("trace_uprobe", argc, argv);
> +
> +	if (argc - 2 > MAX_TRACE_ARGS) {
> +		trace_probe_log_set_index(2);
> +		trace_probe_log_err(0, TOO_MANY_ARGS);
>  		return -E2BIG;
> +	}
>  
>  	if (argv[0][1] == ':')
>  		event = &argv[0][2];
> @@ -582,7 +588,6 @@ static int __trace_uprobe_create(int argc, const char **argv)
>  		return -ECANCELED;
>  	}
>  
> -	trace_probe_log_init("trace_uprobe", argc, argv);
>  	trace_probe_log_set_index(1);	/* filename is the 2nd argument */
>  
>  	*arg++ = '\0';
> 


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