On Tue,  7 Jul 2026 21:24:17 +0800
Yu Peng <[email protected]> wrote:

> parse_synth_field() builds a "__data_loc ..." type string before
> assigning it to field->type. If the seq_buf check fails, the temporary
> string is not owned by field and is leaked. Free it before leaving.
> 
> Suggested-by: Steven Rostedt <[email protected]>
> Signed-off-by: Yu Peng <[email protected]>
> ---
> Changes in v2:
> - Use __free(kfree) and no_free_ptr() as suggested by Steven.
> 
>  kernel/trace/trace_events_synth.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_events_synth.c 
> b/kernel/trace/trace_events_synth.c
> index e6871230bde96..ad2e70258291b 100644
> --- a/kernel/trace/trace_events_synth.c
> +++ b/kernel/trace/trace_events_synth.c
> @@ -828,7 +828,7 @@ static struct synth_field *parse_synth_field(int argc, 
> char **argv,
>       } else if (size == 0) {
>               if (synth_field_is_string(field->type) ||
>                   synth_field_is_stack(field->type)) {
> -                     char *type;
> +                     char *type __free(kfree) = NULL;

Ah, we can't do this here.

(Sashiko pointed this out: 
https://sashiko.dev/#/patchset/20260707132417.2193412-1-pengyu%40kylinos.cn )

>  
>                       len = sizeof("__data_loc ") + strlen(field->type) + 1;
>                       type = kzalloc(len, GFP_KERNEL);

Because after this code we have:

                        type = kzalloc(len, GFP_KERNEL);
                        if (!type)
                                goto free;

Which jumps out of the if block, and that will break the cleanup.

I'll take you original version for now.

-- Steve


> @@ -844,7 +844,7 @@ static struct synth_field *parse_synth_field(int argc, 
> char **argv,
>                       s.buffer[s.len] = '\0';
>  
>                       kfree(field->type);
> -                     field->type = type;
> +                     field->type = no_free_ptr(type);
>  
>                       field->is_dynamic = true;
>                       size = sizeof(u64);


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