6.18-stable review patch. If anyone has any objections, please let me know.
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From: Ma Ke make24@iscas.ac.cn
commit 6d5925b667e4ed9e77c8278cc215191d29454a3f upstream.
intel_th_output_open() calls bus_find_device_by_devt() which internally increments the device reference count via get_device(), but this reference is not properly released in several error paths. When device driver is unavailable, file operations cannot be obtained, or the driver's open method fails, the function returns without calling put_device(), leading to a permanent device reference count leak. This prevents the device from being properly released and could cause resource exhaustion over time.
Found by code review.
Cc: stable stable@kernel.org Fixes: 39f4034693b7 ("intel_th: Add driver infrastructure for Intel(R) Trace Hub devices") Signed-off-by: Ma Ke make24@iscas.ac.cn Link: https://patch.msgid.link/20251112091723.35963-1-make24@iscas.ac.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hwtracing/intel_th/core.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)
--- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -810,13 +810,17 @@ 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) - return -ENODEV; + if (!dev || !dev->driver) { + err = -ENODEV; + goto out_no_device; + }
thdrv = to_intel_th_driver(dev->driver); fops = fops_get(thdrv->fops); - if (!fops) - return -ENODEV; + if (!fops) { + err = -ENODEV; + goto out_put_device; + }
replace_fops(file, fops);
@@ -824,10 +828,16 @@ static int intel_th_output_open(struct i
if (file->f_op->open) { err = file->f_op->open(inode, file); - return err; + if (err) + goto out_put_device; }
return 0; + +out_put_device: + put_device(dev); +out_no_device: + return err; }
static const struct file_operations intel_th_output_fops = {