[PATCH] coresight: cti: Fix DT filter signals silently ignored

[Leo Yan]

On Sun, Apr 26, 2026 at 05:59:34PM +0800, Yingchao Deng wrote:
> In cti_plat_process_filter_sigs(), after allocating a temporary
> cti_trig_grp struct via kzalloc_obj(), the code never assigns tg->nr_sigs
> = nr_filter_sigs. Since kzalloc zero-initialises the struct, tg->nr_sigs
> remains 0. cti_plat_read_trig_group() guards with:
>     if (!tgrp->nr_sigs)
>         return 0;
> 
> so it returns immediately without reading any signal indices from DT.
> 
> Fix by assigning tg->nr_sigs before calling cti_plat_read_trig_group().
> 
> Fixes: a5614770ab97 ("coresight: cti: Add device tree support for custom CTI")
> Signed-off-by: Yingchao Deng <yingchao.deng at oss.qualcomm.com>
> ---
>  drivers/hwtracing/coresight/coresight-cti-platform.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-cti-platform.c b/drivers/hwtracing/coresight/coresight-cti-platform.c
> index 4eff96f48594..d6d5388705c3 100644
> --- a/drivers/hwtracing/coresight/coresight-cti-platform.c
> +++ b/drivers/hwtracing/coresight/coresight-cti-platform.c
> @@ -329,6 +329,7 @@ static int cti_plat_process_filter_sigs(struct cti_drvdata *drvdata,
>  	if (!tg)
>  		return -ENOMEM;
>  
> +	tg->nr_sigs = nr_filter_sigs;
>  	err = cti_plat_read_trig_group(tg, fwnode, CTI_DT_FILTER_OUT_SIGS);

I checked the naming, seems tg->nr_sigs is the right field to store
the number.  LGTM:

Reviewed-by: Leo Yan <leo.yan at arm.com>