Commit 8700af2c authored by Md Haris Iqbal's avatar Md Haris Iqbal Committed by Jason Gunthorpe
Browse files

RDMA/rtrs-clt: Fix possible double free in error case 

Callback function rtrs_clt_dev_release() for put_device() calls kfree(clt)
to free memory. We shouldn't call kfree(clt) again, and we can't use the
clt after kfree too.

Replace device_register() with device_initialize() and device_add() so that
dev_set_name can() be used appropriately.

Move mutex_destroy() to the release function so it can be called in
the alloc_clt err path.

Fixes: eab09824 ("RDMA/rtrs-clt: Refactor the failure cases in alloc_clt")
Link: https://lore.kernel.org/r/20220217030929.323849-1-haris.iqbal@ionos.com


Reported-by: default avatarMiaoqian Lin <linmq006@gmail.com>
Signed-off-by: default avatarMd Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: default avatarJack Wang <jinpu.wang@ionos.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 32f57cb1

drivers/infiniband/ulp/rtrs/rtrs-clt.c

+20 −17
Original line number Diff line number Diff line
@@ -2682,6 +2682,8 @@ static void rtrs_clt_dev_release(struct device *dev) 
	struct rtrs_clt_sess *clt = container_of(dev, struct rtrs_clt_sess,

						 dev);



	mutex_destroy(&clt->paths_ev_mutex);

	mutex_destroy(&clt->paths_mutex);

	kfree(clt);

}
@@ -2711,6 +2713,8 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num, 
		return ERR_PTR(-ENOMEM);

	}



	clt->dev.class = rtrs_clt_dev_class;

	clt->dev.release = rtrs_clt_dev_release;

	uuid_gen(&clt->paths_uuid);

	INIT_LIST_HEAD_RCU(&clt->paths_list);

	clt->paths_num = paths_num;
@@ -2727,43 +2731,41 @@ static struct rtrs_clt_sess *alloc_clt(const char *sessname, size_t paths_num, 
	init_waitqueue_head(&clt->permits_wait);

	mutex_init(&clt->paths_ev_mutex);

	mutex_init(&clt->paths_mutex);

	device_initialize(&clt->dev);



	clt->dev.class = rtrs_clt_dev_class;

	clt->dev.release = rtrs_clt_dev_release;

	err = dev_set_name(&clt->dev, "%s", sessname);

	if (err)

		goto err;

		goto err_put;



	/*

	 * Suppress user space notification until

	 * sysfs files are created

	 */

	dev_set_uevent_suppress(&clt->dev, true);

	err = device_register(&clt->dev);

	if (err) {

		put_device(&clt->dev);

		goto err;

	}

	err = device_add(&clt->dev);

	if (err)

		goto err_put;



	clt->kobj_paths = kobject_create_and_add("paths", &clt->dev.kobj);

	if (!clt->kobj_paths) {

		err = -ENOMEM;

		goto err_dev;

		goto err_del;

	}

	err = rtrs_clt_create_sysfs_root_files(clt);

	if (err) {

		kobject_del(clt->kobj_paths);

		kobject_put(clt->kobj_paths);

		goto err_dev;

		goto err_del;

	}

	dev_set_uevent_suppress(&clt->dev, false);

	kobject_uevent(&clt->dev.kobj, KOBJ_ADD);



	return clt;

err_dev:

	device_unregister(&clt->dev);

err:

err_del:

	device_del(&clt->dev);

err_put:

	free_percpu(clt->pcpu_path);

	kfree(clt);

	put_device(&clt->dev);

	return ERR_PTR(err);

}
@@ -2771,9 +2773,10 @@ static void free_clt(struct rtrs_clt_sess *clt) 
{

	free_permits(clt);

	free_percpu(clt->pcpu_path);

	mutex_destroy(&clt->paths_ev_mutex);

	mutex_destroy(&clt->paths_mutex);

	/* release callback will free clt in last put */



	/*

	 * release callback will free clt and destroy mutexes in last put

	 */

	device_unregister(&clt->dev);

}