[PATCH 5.15 089/139] RDMA/rtrs-clt: Fix possible double free in error case

Greg Kroah-Hartman
2022-02-28T17:58:35Z

From: Md Haris Iqbal <haris.iqbal@ionos.com>

[ Upstream commit 8700af2cc18c919b2a83e74e0479038fd113c15d ]

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: eab098246625 ("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: Miaoqian Lin <linmq006@gmail.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Reviewed-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 37 ++++++++++++++------------
1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
index 55ebe01ec9951..3272514f05405 100644
--- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
+++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
@@ -2664,6 +2664,8 @@ static void rtrs_clt_dev_release(struct device *dev)
{
struct rtrs_clt *clt = container_of(dev, struct rtrs_clt, dev);

+ mutex_destroy(&clt->paths_ev_mutex);
+ mutex_destroy(&clt->paths_mutex);
kfree(clt);
}

@@ -2693,6 +2695,8 @@ static struct rtrs_clt *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;
@@ -2709,43 +2713,41 @@ static struct rtrs_clt *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);
}

@@ -2753,9 +2755,10 @@ static void free_clt(struct rtrs_clt *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);
}

--
2.34.1