Re: [PATCH] kernelshark: Fix TEP filter array parsing logic

[Steven Rostedt <rostedt@goodmis.org>]

On Tue, 24 Feb 2026 17:05:25 +0000
Ciunas Bennett <ciunas@linux.ibm.com> wrote:

Thanks, I'm adding Yordan to the Cc as he's maintaining KernelShark.

-- Steve


> When saving a session with more than a single TEP advanced filter,
> KernelShark triggers a json-c assertion:
> 
> "json_object_array_get_idx: Assertion
> `json_object_get_type(jso) == json_type_array' failed."
> 
> This is caused because the code reuses the `jfilter` variable inside
> the loop to fetch each array element:
> 
>     jfilter = json_object_array_get_idx(jfilter, i);
> 
> This overwrites the original array object. On the next iteration,
> `jfilter` is no longer a json_type_array, causing the assertion.
> 
> Fix this by introducing a temporary variable `jitem` to store each
> array element, leaving `jfilter` to point to the actual array.
> 
> Signed-off-by: Ciunas Bennett <ciunas@linux.ibm.com>
> ---
>  src/libkshark-configio.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/src/libkshark-configio.c b/src/libkshark-configio.c
> index 88c2c9a..568ec73 100644
> --- a/src/libkshark-configio.c
> +++ b/src/libkshark-configio.c
> @@ -1528,7 +1528,7 @@ bool kshark_export_adv_filters(struct kshark_context *kshark_ctx, int sd,
>  static bool kshark_adv_filters_from_json(struct kshark_data_stream *stream,
>  					 struct json_object *jobj)
>  {
> -	json_object *jfilter, *jname, *jcond;
> +	json_object *jfilter, *jname, *jcond, *jitem;
>  	int i, length, n, ret = 0;
>  	char *filter_str = NULL;
>  
> @@ -1548,10 +1548,10 @@ static bool kshark_adv_filters_from_json(struct kshark_data_stream *stream,
>  	/* Set the filter. */
>  	length = json_object_array_length(jfilter);
>  	for (i = 0; i < length; ++i) {
> -		jfilter = json_object_array_get_idx(jfilter, i);
> +		jitem = json_object_array_get_idx(jfilter, i);
>  
> -		if (!json_object_object_get_ex(jfilter, "name", &jname) ||
> -		    !json_object_object_get_ex(jfilter, "condition", &jcond))
> +		if (!json_object_object_get_ex(jitem, "name", &jname) ||
> +		    !json_object_object_get_ex(jitem, "condition", &jcond))
>  			goto fail;
>  
>  		n = asprintf(&filter_str, "%s:%s",