5.4-stable review patch. If anyone has any objections, please let me know.
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From: Weihang Li liweihang@huawei.com
[ Upstream commit 60dff56d77292062789232f68354f567e1ccf1d2 ]
The refcount_t API will WARN on underflow and overflow of a reference counter, and avoid use-after-free risks.
Link: https://lore.kernel.org/r/1622194663-2383-2-git-send-email-liweihang@huawei.... Signed-off-by: Weihang Li liweihang@huawei.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Stable-dep-of: 6883b680e703 ("RDMA/iwcm: Fix use-after-free of work objects after cm_id destruction") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/iwcm.c | 9 ++++----- drivers/infiniband/core/iwcm.h | 2 +- 2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c index 44362f693df9f..3e4941754b48d 100644 --- a/drivers/infiniband/core/iwcm.c +++ b/drivers/infiniband/core/iwcm.c @@ -211,8 +211,7 @@ static void free_cm_id(struct iwcm_id_private *cm_id_priv) */ static int iwcm_deref_id(struct iwcm_id_private *cm_id_priv) { - BUG_ON(atomic_read(&cm_id_priv->refcount)==0); - if (atomic_dec_and_test(&cm_id_priv->refcount)) { + if (refcount_dec_and_test(&cm_id_priv->refcount)) { BUG_ON(!list_empty(&cm_id_priv->work_list)); free_cm_id(cm_id_priv); return 1; @@ -225,7 +224,7 @@ static void add_ref(struct iw_cm_id *cm_id) { struct iwcm_id_private *cm_id_priv; cm_id_priv = container_of(cm_id, struct iwcm_id_private, id); - atomic_inc(&cm_id_priv->refcount); + refcount_inc(&cm_id_priv->refcount); }
static void rem_ref(struct iw_cm_id *cm_id) @@ -257,7 +256,7 @@ struct iw_cm_id *iw_create_cm_id(struct ib_device *device, cm_id_priv->id.add_ref = add_ref; cm_id_priv->id.rem_ref = rem_ref; spin_lock_init(&cm_id_priv->lock); - atomic_set(&cm_id_priv->refcount, 1); + refcount_set(&cm_id_priv->refcount, 1); init_waitqueue_head(&cm_id_priv->connect_wait); init_completion(&cm_id_priv->destroy_comp); INIT_LIST_HEAD(&cm_id_priv->work_list); @@ -1097,7 +1096,7 @@ static int cm_event_handler(struct iw_cm_id *cm_id, } }
- atomic_inc(&cm_id_priv->refcount); + refcount_inc(&cm_id_priv->refcount); if (list_empty(&cm_id_priv->work_list)) { list_add_tail(&work->list, &cm_id_priv->work_list); queue_work(iwcm_wq, &work->work); diff --git a/drivers/infiniband/core/iwcm.h b/drivers/infiniband/core/iwcm.h index 82c2cd1b0a804..bf74639be1287 100644 --- a/drivers/infiniband/core/iwcm.h +++ b/drivers/infiniband/core/iwcm.h @@ -52,7 +52,7 @@ struct iwcm_id_private { wait_queue_head_t connect_wait; struct list_head work_list; spinlock_t lock; - atomic_t refcount; + refcount_t refcount; struct list_head work_free_list; };