4.18-stable review patch. If anyone has any objections, please let me know.
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From: Steve Wise swise@opengridcomputing.com
commit 67e3816842fe6414d629c7515b955952ec40c7d7 upstream.
Currently a uverbs completion event queue is flushed of events in ib_uverbs_comp_event_close() with the queue spinlock held and then released. Yet setting ev_queue->is_closed is not set until later in uverbs_hot_unplug_completion_event_file().
In between the time ib_uverbs_comp_event_close() releases the lock and uverbs_hot_unplug_completion_event_file() acquires the lock, a completion event can arrive and be inserted into the event queue by ib_uverbs_comp_handler().
This can cause a "double add" list_add warning or crash depending on the kernel configuration, or a memory leak because the event is never dequeued since the queue is already closed down.
So add setting ev_queue->is_closed = 1 to ib_uverbs_comp_event_close().
Cc: stable@vger.kernel.org Fixes: 1e7710f3f656 ("IB/core: Change completion channel to use the reworked objects schema") Signed-off-by: Steve Wise swise@opengridcomputing.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/infiniband/core/uverbs_main.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -429,6 +429,7 @@ static int ib_uverbs_comp_event_close(st list_del(&entry->obj_list); kfree(entry); } + file->ev_queue.is_closed = 1; spin_unlock_irq(&file->ev_queue.lock);
uverbs_close_fd(filp);