From: Jason Gunthorpe jgg@mellanox.com
[ Upstream commit bede86a39d9dc3387ac00dcb8e1ac221676b2f25 ]
When creating a cm_id during REQ the id immediately becomes visible to the other MAD handlers, and shortly after the state is moved to IB_CM_REQ_RCVD
This allows cm_rej_handler() to run concurrently and free the work:
CPU 0 CPU1 cm_req_handler() ib_create_cm_id() cm_match_req() id_priv->state = IB_CM_REQ_RCVD cm_rej_handler() cm_acquire_id() spin_lock(&id_priv->lock) switch (id_priv->state) case IB_CM_REQ_RCVD: cm_reset_to_idle() kfree(id_priv->timewait_info); goto destroy destroy: kfree(id_priv->timewait_info); id_priv->timewait_info = NULL
Causing a double free or worse.
Do not free the timewait_info without also holding the id_priv->lock. Simplify this entire flow by making the free unconditional during cm_destroy_id() and removing the confusing special case error unwind during creation of the timewait_info.
This also fixes a leak of the timewait if cm_destroy_id() is called in IB_CM_ESTABLISHED with an XRC TGT QP. The state machine will be left in ESTABLISHED while it needed to transition through IB_CM_TIMEWAIT to release the timewait pointer.
Also fix a leak of the timewait_info if the caller mis-uses the API and does ib_send_cm_reqs().
Fixes: a977049dacde ("[PATCH] IB: Add the kernel CM implementation") Link: https://lore.kernel.org/r/20200310092545.251365-4-leon@kernel.org Signed-off-by: Leon Romanovsky leonro@mellanox.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/cm.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index 7251068b6af0f..601a36e7f098c 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -1100,14 +1100,22 @@ static void cm_destroy_id(struct ib_cm_id *cm_id, int err) break; }
- spin_lock_irq(&cm.lock); + spin_lock_irq(&cm_id_priv->lock); + spin_lock(&cm.lock); + /* Required for cleanup paths related cm_req_handler() */ + if (cm_id_priv->timewait_info) { + cm_cleanup_timewait(cm_id_priv->timewait_info); + kfree(cm_id_priv->timewait_info); + cm_id_priv->timewait_info = NULL; + } if (!list_empty(&cm_id_priv->altr_list) && (!cm_id_priv->altr_send_port_not_ready)) list_del(&cm_id_priv->altr_list); if (!list_empty(&cm_id_priv->prim_list) && (!cm_id_priv->prim_send_port_not_ready)) list_del(&cm_id_priv->prim_list); - spin_unlock_irq(&cm.lock); + spin_unlock(&cm.lock); + spin_unlock_irq(&cm_id_priv->lock);
cm_free_id(cm_id->local_id); cm_deref_id(cm_id_priv); @@ -1424,7 +1432,7 @@ int ib_send_cm_req(struct ib_cm_id *cm_id, /* Verify that we're not in timewait. */ cm_id_priv = container_of(cm_id, struct cm_id_private, id); spin_lock_irqsave(&cm_id_priv->lock, flags); - if (cm_id->state != IB_CM_IDLE) { + if (cm_id->state != IB_CM_IDLE || WARN_ON(cm_id_priv->timewait_info)) { spin_unlock_irqrestore(&cm_id_priv->lock, flags); ret = -EINVAL; goto out; @@ -1442,12 +1450,12 @@ int ib_send_cm_req(struct ib_cm_id *cm_id, param->ppath_sgid_attr, &cm_id_priv->av, cm_id_priv); if (ret) - goto error1; + goto out; if (param->alternate_path) { ret = cm_init_av_by_path(param->alternate_path, NULL, &cm_id_priv->alt_av, cm_id_priv); if (ret) - goto error1; + goto out; } cm_id->service_id = param->service_id; cm_id->service_mask = ~cpu_to_be64(0); @@ -1465,7 +1473,7 @@ int ib_send_cm_req(struct ib_cm_id *cm_id,
ret = cm_alloc_msg(cm_id_priv, &cm_id_priv->msg); if (ret) - goto error1; + goto out;
req_msg = (struct cm_req_msg *) cm_id_priv->msg->mad; cm_format_req(req_msg, cm_id_priv, param); @@ -1488,7 +1496,6 @@ int ib_send_cm_req(struct ib_cm_id *cm_id, return 0;
error2: cm_free_msg(cm_id_priv->msg); -error1: kfree(cm_id_priv->timewait_info); out: return ret; } EXPORT_SYMBOL(ib_send_cm_req); @@ -1977,7 +1984,7 @@ static int cm_req_handler(struct cm_work *work) pr_debug("%s: local_id %d, no listen_cm_id_priv\n", __func__, be32_to_cpu(cm_id->local_id)); ret = -EINVAL; - goto free_timeinfo; + goto destroy; }
cm_id_priv->id.cm_handler = listen_cm_id_priv->id.cm_handler; @@ -2061,8 +2068,6 @@ static int cm_req_handler(struct cm_work *work) rejected: atomic_dec(&cm_id_priv->refcount); cm_deref_id(listen_cm_id_priv); -free_timeinfo: - kfree(cm_id_priv->timewait_info); destroy: ib_destroy_cm_id(cm_id); return ret;