On Wed, Apr 15, 2026 at 09:21:21AM +0800, Jie Gan wrote:

[...]

...

...

...

@@ -918,8 +918,10 @@ static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_pa cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset); if (cfg_hash) { ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);

• if (ret)
  

• if (ret) {
  

• 	etm4_release_trace_id(drvdata);
  

If so, even an ID is reserved for failures, and the ID map is big enough for each CPU, we don't need to worry memory leak or ID used out issue ?

However, in theory, this could lead to an ID leak, so it would be better to release it in error cases.

What I am thinking is as SoCs continue to grow more complex with an increasing number of subsystems, trace IDs may be exhausted in the near future. (that's why we have dynamic trace ID allocation/release).

Thanks for the input.

I am wandering if we can use "dev->devt" as the trace ID. A device's major/minor number is unique in kernel and dev_t is defined as u32:

typedef u32 __kernel_dev_t;

And we can consolidate this for both SYSFS and PERF modes.

Thanks, Leo