[PATCH 6.1 172/280] intel_th: fix device leak on output open()

Greg Kroah-Hartman
2026-02-04T15:12:43Z

From: Johan Hovold <johan@kernel.org>

commit 95fc36a234da24bbc5f476f8104a5a15f99ed3e3 upstream.

Make sure to drop the reference taken when looking up the th device
during output device open() on errors and on close().

Note that a recent commit fixed the leak in a couple of open() error
paths but not all of them, and the reference is still leaking on
successful open().

Fixes: 39f4034693b7 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices")
Fixes: 6d5925b667e4 ("intel_th: Fix error handling in intel_th_output_open")
Cc: stable@vger.kernel.org # 4.4: 6d5925b667e4
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ma Ke <make24@iscas.ac.cn>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20251208153524.68637-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/hwtracing/intel_th/core.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

--- a/drivers/hwtracing/intel_th/core.c
+++ b/drivers/hwtracing/intel_th/core.c
@@ -810,9 +810,12 @@ static int intel_th_output_open(struct i
int err;

dev = bus_find_device_by_devt(&intel_th_bus, inode->i_rdev);
- if (!dev || !dev->driver) {
+ if (!dev)
+ return -ENODEV;
+
+ if (!dev->driver) {
err = -ENODEV;
- goto out_no_device;
+ goto out_put_device;
}

thdrv = to_intel_th_driver(dev->driver);
@@ -836,12 +839,22 @@ static int intel_th_output_open(struct i

out_put_device:
put_device(dev);
-out_no_device:
+
return err;
}

+static int intel_th_output_release(struct inode *inode, struct file *file)
+{
+ struct intel_th_device *thdev = file->private_data;
+
+ put_device(&thdev->dev);
+
+ return 0;
+}
+
static const struct file_operations intel_th_output_fops = {
.open = intel_th_output_open,
+ .release = intel_th_output_release,
.llseek = noop_llseek,
};