On 12/15/2025 5:51 PM, Leo Yan wrote:
On Mon, Dec 15, 2025 at 11:02:08AM +0200, James Clark wrote:
On 15/12/2025 04:27, Ma Ke wrote:
In etm_setup_aux(), when a user sink is obtained via coresight_get_sink_by_id(), it increments the reference count of the sink device. However, if the sink is used in path building, the path holds a reference, but the initial reference from coresight_get_sink_by_id() is not released, causing a reference count leak. We should release the initial reference after the path is built.
Found by code review.
Cc: stable@vger.kernel.org Fixes: 0e6c20517596 ("coresight: etm-perf: Allow an event to use different sinks") Signed-off-by: Ma Ke make24@iscas.ac.cn
Changes in v2:
- modified the patch as suggestions.
I think Leo's comment on the previous v2 is still unaddressed. But releasing it in coresight_get_sink_by_id() would make it consistent with coresight_find_csdev_by_fwnode() and prevent further mistakes.
The point is the coresight core layer uses coresight_grab_device() to increase the device's refcnt. This is why we don't need to grab a device when setup AUX.
That make sense. We dont need to hold the refcnt for a while and it should be released immediately after locating the required device.
Thanks, Jie
It also leads me to see that users of coresight_find_device_by_fwnode() should also release it, but only one out of two appears to.
Good finding!
Thanks, Leo