From: Jason Gunthorpe jgg@mellanox.com
[ Upstream commit eb356e6dc15a30af604f052cd0e170450193c254 ]
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") Link: https://lore.kernel.org/r/0-v1-ace813388969+48859-uverbs_poll_fix%25jgg@mell... Reviewed-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/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 f2a2d1246c19..adb08c3fc085 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -307,6 +307,8 @@ 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;