RDMA/mlx5: Fix memory leak in GET_DATA_DIRECT_SYSFS_PATH handler

[ Upstream commit 9b9d253908478f504297ac283c514e5953ddafa6 ]

The UVERBS_HANDLER(MLX5_IB_METHOD_GET_DATA_DIRECT_SYSFS_PATH) function
allocates memory for the device path using kobject_get_path(). If the
length of the device path exceeds the output buffer length, the function
returns -ENOSPC but does not free the allocated memory, resulting in a
memory leak.

Add a kfree() call to the error path to ensure the allocated memory is
properly freed.

Compile tested only. Issue found using a prototype static analysis tool
and code review.

Fixes: ec7ad65 ("RDMA/mlx5: Introduce GET_DATA_DIRECT_SYSFS_PATH ioctl")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Link: https://patch.msgid.link/20260126074801.627898-1-zilin@seu.edu.cn
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: GoodLuck612

drivers/infiniband/hw/mlx5/std_types.c

@@ -214,7 +214,7 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_GET_DATA_DIRECT_SYSFS_PATH)(
 	int out_len = uverbs_attr_get_len(attrs,
 			MLX5_IB_ATTR_GET_DATA_DIRECT_SYSFS_PATH);
 	u32 dev_path_len;
-	char *dev_path;
+	char *dev_path = NULL;
 	int ret;
 
 	c = to_mucontext(ib_uverbs_get_ucontext(attrs));
@@ -242,9 +242,9 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_GET_DATA_DIRECT_SYSFS_PATH)(
 
 	ret = uverbs_copy_to(attrs, MLX5_IB_ATTR_GET_DATA_DIRECT_SYSFS_PATH, dev_path,
 			     dev_path_len);
-	kfree(dev_path);
 
 end:
+	kfree(dev_path);
 	mutex_unlock(&dev->data_direct_lock);
 	return ret;
 }