From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
If is_closed is set, and the event list is empty, then read() will return
-EIO without blocking. After setting is_closed in
ib_uverbs_free_event_queue(), we do trigger a wake_up on the poll_wait,
but the fops->poll() function does not check it, so poll will continue to
sleep on an empty list.
Fixes: 14e23bd6d221 ("RDMA/core: Fix locking in ib_uverbs_event_read")
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
---
drivers/infiniband/core/uverbs_main.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 2d4083bf4a0487..8710a3427146e7 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -296,6 +296,8 @@ static __poll_t ib_uverbs_event_poll(struct ib_uverbs_event_queue *ev_queue,
spin_lock_irq(&ev_queue->lock);
if (!list_empty(&ev_queue->event_list))
pollflags = EPOLLIN | EPOLLRDNORM;
+ else if (ev_queue->is_closed)
+ pollflags = EPOLLERR;
spin_unlock_irq(&ev_queue->lock);
return pollflags;
--
2.25.2
