4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Fixes: 1e7710f3f656 ("IB/core: Change completion channel to use the reworked objects schema")
Signed-off-by: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
