From: Shay Drory shayd@nvidia.com
[ Upstream commit def4cd43f522253645b72c97181399c241b54536 ]
Currently, polling a umad device will always works, even if the device was disassociated. A disassociated device should immediately return EPOLLERR from poll(). Otherwise userspace is endlessly hung on poll() with no idea that the device has been removed from the system.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://lore.kernel.org/r/20210125121339.837518-3-leon@kernel.org Signed-off-by: Shay Drory shayd@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/user_mad.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index db2ac5218c371..471a824be86c4 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -384,6 +384,11 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf, mutex_lock(&file->mutex); }
+ if (file->agents_dead) { + mutex_unlock(&file->mutex); + return -EIO; + } + packet = list_entry(file->recv_list.next, struct ib_umad_packet, list); list_del(&packet->list);
@@ -642,10 +647,14 @@ static __poll_t ib_umad_poll(struct file *filp, struct poll_table_struct *wait) /* we will always be able to post a MAD send */ __poll_t mask = EPOLLOUT | EPOLLWRNORM;
+ mutex_lock(&file->mutex); poll_wait(filp, &file->recv_wait, wait);
if (!list_empty(&file->recv_list)) mask |= EPOLLIN | EPOLLRDNORM; + if (file->agents_dead) + mask = EPOLLERR; + mutex_unlock(&file->mutex);
return mask; } @@ -1262,6 +1271,7 @@ static void ib_umad_kill_port(struct ib_umad_port *port) list_for_each_entry(file, &port->file_list, port_list) { mutex_lock(&file->mutex); file->agents_dead = 1; + wake_up_interruptible(&file->recv_wait); mutex_unlock(&file->mutex);
for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id)