diff options
author | Jason Gunthorpe <jgg@mellanox.com> | 2020-03-10 11:25:33 +0200 |
---|---|---|
committer | Jason Gunthorpe <jgg@mellanox.com> | 2020-03-17 17:05:51 -0300 |
commit | bede86a39d9dc3387ac00dcb8e1ac221676b2f25 (patch) | |
tree | ccfb158435f46ed7757920aa6bf5bbbf8dabf68f | |
parent | ca21cb7fb127fcba013acc66f9ebe2e3a9ae1e49 (diff) | |
download | linux-bede86a39d9dc3387ac00dcb8e1ac221676b2f25.tar.bz2 |
RDMA/cm: Remove a race freeing timewait_info
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>
-rw-r--r-- | drivers/infiniband/core/cm.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c index ba35cad951e6..0685cb2a88c0 100644 --- a/drivers/infiniband/core/cm.c +++ b/drivers/infiniband/core/cm.c @@ -1054,14 +1054,22 @@ retest: 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); @@ -1410,7 +1418,7 @@ 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; @@ -1428,12 +1436,12 @@ 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); @@ -1451,7 +1459,7 @@ 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); @@ -1474,7 +1482,6 @@ 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); @@ -2003,7 +2010,7 @@ 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; @@ -2093,8 +2100,6 @@ static int cm_req_handler(struct cm_work *work) rejected: refcount_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; |