[PATCH] coresight: fix resource leaks on path build failure

[Jie Gan <jie.gan@oss.qualcomm.com>]

Two related leaks when _coresight_build_path() encounters an error after
coresight_grab_device() has already incremented the pm_runtime, module,
and device references for a node:

1. In _coresight_build_path(), if kzalloc_obj() for the path node fails
   after coresight_grab_device() succeeds, coresight_drop_device() was
   never called, permanently leaking all three references.

2. In coresight_build_path(), on failure the partial path was freed with
   kfree(path) instead of coresight_release_path(path).  kfree() only
   frees the coresight_path struct itself; it does not iterate path_list
   to call coresight_drop_device() and kfree() for each coresight_node
   already added by deeper recursive calls, leaking both the pm_runtime,
   module, and device references and the node memory for every element
   on the partial path.

Fix both by adding coresight_drop_device() in the OOM unwind of
_coresight_build_path(), and replacing kfree(path) with
coresight_release_path(path) in coresight_build_path().

Fixes: 32b0707a4182 ("coresight: Add try_get_module() in coresight_grab_device()")
Fixes: b3e94405941e ("coresight: associating path with session rather than tracer")
Signed-off-by: Jie Gan <jie.gan@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 46f247f73cf6..c1354ea8e11d 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -825,8 +825,10 @@ static int _coresight_build_path(struct coresight_device *csdev,
 		return ret;
 
 	node = kzalloc_obj(struct coresight_node);
-	if (!node)
+	if (!node) {
+		coresight_drop_device(csdev);
 		return -ENOMEM;
+	}
 
 	node->csdev = csdev;
 	list_add(&node->link, &path->path_list);
@@ -851,7 +853,7 @@ struct coresight_path *coresight_build_path(struct coresight_device *source,
 
 	rc = _coresight_build_path(source, source, sink, path);
 	if (rc) {
-		kfree(path);
+		coresight_release_path(path);
 		return ERR_PTR(rc);
 	}
 

---
base-commit: e98d21c170b01ddef366f023bbfcf6b31509fa83
change-id: 20260513-fix-memory-leak-issue-034b4a45265e

Best regards,
-- 
Jie Gan <jie.gan@oss.qualcomm.com>